Here's my config for my WAN interface (port 4) and LAN interfaces (ports 1 & 2):-


edit "port4"
        set vdom "root"
        set mode pppoe
        set distance 1
        set allowaccess ping
        set vlanforward enable
        set ident-accept enable
        set type physical
        set scan-botnet-connections block
        set description "Connection to XXX ISP"
        set alias "WAN"
        set estimated-upstream-bandwidth 18000
        set estimated-downstream-bandwidth 72000
        set role wan
        set snmp-index 4
        config ipv6
            set ip6-mode pppoe
            set ip6-allowaccess ping
            set dhcp6-prefix-delegation enable
            set dhcp6-prefix-hint 2001:XXX:XXXX:ed3f::/64
            set autoconf enable
        end
        set username "XXXX@XXXX"
        set password ENC tq5ZO9A2J9sK7nniSkXXXXXXXXXXXiL1uWouRrsCrTmzxnKU0YFClOgMgnKKM85LigteqPIzB+8pwZkgu/uICkfM9IqKJ2IczCi2mcQpjWdegYBWYBQpx0Kepb4IjUczW4bTLQ6QarQvITrBcmXbQU9XkCd5nCHGIbZSOE3DaddpMFAAw6WY+TSoFtgh/hJ5JLXfWlwg==
        set padt-retry-timeout 0
        set dns-server-override disable
    next

and LAN ports 1 &2 :-


edit "port1"
        set vdom "root"
        set ip 192.168.XXX.1 255.255.255.0
        set allowaccess ping https ssh
        set vlanforward enable
        set type physical
        set scan-botnet-connections block
        set alias "LAN1"
        set device-identification enable
        set device-identification-active-scan enable
        set lldp-transmission enable
        set fortiheartbeat enable
        set role lan
        set snmp-index 1
        config ipv6
            set ip6-mode delegated
            set ip6-allowaccess ping https ssh
            set ip6-send-adv enable
            set ip6-manage-flag enable
            set ip6-other-flag enable
            set ip6-upstream-interface "port4"
            set ip6-subnet ::1.0.0.1/120
            config ip6-delegated-prefix-list
                edit 1
                    set upstream-interface "port4"
                    set autonomous-flag enable
                    set onlink-flag enable
                    set subnet ::1.0.0.0/120
                next
            end
        end
    next
    edit "port2"
        set vdom "root"
        set ip 192.168.XXX.1 255.255.255.0
        set vlanforward enable
        set type physical
        set scan-botnet-connections block
        set alias "LAN2"
        set device-identification enable
        set device-identification-active-scan enable
        set lldp-transmission enable
        set fortiheartbeat enable
        set role lan
        set snmp-index 2
        config ipv6
            set ip6-mode delegated
            set ip6-send-adv enable
            set ip6-manage-flag enable
            set ip6-other-flag enable
            set ip6-upstream-interface "port4"
            set ip6-subnet ::2.0.0.1/120
            config ip6-delegated-prefix-list
                edit 1
                    set upstream-interface "port4"
                    set autonomous-flag enable
                    set onlink-flag enable
                    set subnet ::2.0.0.0/120
                next
            end
        end




-------------------------------------- Port "get" showing current addresses etc --------------------------------------------------------



WAN (Port 4) details

router (port4) # get
name                : port4
vdom                : root
cli-conn-status     : 2
fortilink           : disable
mode                : pppoe
distance            : 1
priority            : 0
dhcp-relay-service  : disable
ip                  : XXX.XXX.199.37 255.255.255.255
allowaccess         : ping
fail-detect         : disable
arpforward          : enable
broadcast-forward   : disable
bfd                 : global
l2forward           : disable
icmp-redirect       : enable
vlanforward         : enable
stpforward          : disable
ips-sniffer-mode    : disable
ident-accept        : enable
ipmac               : disable
subst               : disable
substitute-dst-mac  : 00:00:00:00:00:00
status              : up
netbios-forward     : disable
wins-ip             : 0.0.0.0
type                : physical
netflow-sampler     : disable
sflow-sampler       : disable
scan-botnet-connections: block
src-check           : enable
sample-rate         : 2000
polling-interval    : 20
sample-direction    : both
explicit-web-proxy  : disable
explicit-ftp-proxy  : disable
tcp-mss             : 0
inbandwidth         : 0
outbandwidth        : 0
spillover-threshold : 0
ingress-spillover-threshold: 0
weight              : 0
external            : disable
devindex            : 6
description         : Connection to A&A ISP
alias               : WAN
l2tp-client         : disable
security-mode       : none
device-identification: disable
fortiheartbeat      : disable
estimated-upstream-bandwidth: 18000
estimated-downstream-bandwidth: 72000
vrrp-virtual-mac    : disable
vrrp:
role                : wan
snmp-index          : 4
auto-auth-extension-device: disable
ap-discover         : enable
ipv6:
    ip6-mode            : pppoe
    nd-mode             : basic
    ip6-allowaccess     : ping
    ip6-reachable-time  : 0
    ip6-retrans-time    : 0
    ip6-hop-limit       : 0
    dhcp6-prefix-delegation: enable
delegated-prefix            : 2001:XXX:XXXX:ed3f::/64
preferred-life-time         : 3600
valid-life-time     : 3600
delegated-DNS1      : 2001:XXX::2020
delegated-DNS2      : 2001:XXX::2021
delegated-domain          :
    dhcp6-prefix-hint   : 2001:XXX:XXXX:ed3f::/64
    dhcp6-prefix-hint-plt: 604800
    dhcp6-prefix-hint-vlt: 2592000
    autoconf            : enable
ipunnumbered        : 0.0.0.0
username            : XXXX@XXXX
password            : *
idle-timeout        : 0
detected-peer-mtu   : 1492
disc-retry-timeout  : 1
padt-retry-timeout  : 0
service-name        :
ac-name             :
lcp-echo-interval   : 5
lcp-max-echo-fails  : 3
defaultgw           : enable
PPPOE Gateway       : XXX.XXX.81.187
dns-server-override : disable
Acquired DNS1       : XXX.XXX.20.20
Acquired DNS2       : XXX.XXX.20.21
auth-type           : auto
macaddr             : 08:5b:0e:ca:XX:XX
speed               : auto
mtu-override        : disable
wccp                : disable
drop-overlapped-fragment: disable
drop-fragment       : disable

LAN 1 (Port  1)
router (port1) # get
name                : port1
vdom                : root
cli-conn-status     : 0
fortilink           : disable
mode                : static
dhcp-relay-service  : disable
ip                  : 192.168.XXX.1 255.255.255.0
allowaccess         : ping https ssh
fail-detect         : disable
pptp-client         : disable
arpforward          : enable
broadcast-forward   : disable
bfd                 : global
l2forward           : disable
icmp-redirect       : enable
vlanforward         : enable
stpforward          : disable
ips-sniffer-mode    : disable
ident-accept        : disable
ipmac               : disable
subst               : disable
substitute-dst-mac  : 00:00:00:00:00:00
status              : up
netbios-forward     : disable
wins-ip             : 0.0.0.0
type                : physical
netflow-sampler     : disable
sflow-sampler       : disable
scan-botnet-connections: block
src-check           : enable
sample-rate         : 2000
polling-interval    : 20
sample-direction    : both
explicit-web-proxy  : disable
explicit-ftp-proxy  : disable
tcp-mss             : 0
inbandwidth         : 0
outbandwidth        : 0
spillover-threshold : 0
ingress-spillover-threshold: 0
weight              : 0
external            : disable
devindex            : 3
description         :
alias               : LAN1
l2tp-client         : disable
security-mode       : none
device-identification: enable
device-user-identification: enable
device-identification-active-scan: enable
device-access-list  :
lldp-transmission   : enable
fortiheartbeat      : enable
broadcast-forticlient-discovery: disable
endpoint-compliance : disable
estimated-upstream-bandwidth: 0
estimated-downstream-bandwidth: 0
vrrp-virtual-mac    : disable
vrrp:
role                : lan
snmp-index          : 1
secondary-IP        : disable
auto-auth-extension-device: disable
ap-discover         : enable
ipv6:
    ip6-mode            : delegated
    nd-mode             : basic
    ip6-allowaccess     : ping https ssh
    ip6-reachable-time  : 0
    ip6-retrans-time    : 0
    ip6-hop-limit       : 0
    dhcp6-prefix-delegation: disable
delegated-prefix            : ::/0
preferred-life-time         : 0
valid-life-time     : 0
delegated-DNS1      : ::
delegated-DNS2      : ::
delegated-domain          :
    dhcp6-information-request: disable
    ip6-send-adv        : enable
    ip6-manage-flag     : enable
    ip6-other-flag      : enable
    ip6-max-interval    : 600
    ip6-min-interval    : 198
    ip6-link-mtu        : 0
    ip6-default-life    : 1800
    ip6-upstream-interface: port4
    ip6-subnet          : ::1.0.0.1/120
    ip6-delegated-prefix-list:
        == [ 1 ]
        prefix-id:         1           upstream-interface: port4                    autonomous-flag: enable                    onlink-flag: enable                    subnet: ::1.0.0.0/120
macaddr             : 08:5b:0e:ca:XX:XX
speed               : auto
mtu-override        : disable
wccp                : disable
drop-overlapped-fragment: disable
drop-fragment       : disable

LAN 2 (Port 2)

router (port2) # get
name                : port2
vdom                : root
cli-conn-status     : 0
fortilink           : disable
mode                : static
dhcp-relay-service  : disable
ip                  : 192.168.XXX.1 255.255.255.0
allowaccess         :
fail-detect         : disable
pptp-client         : disable
arpforward          : enable
broadcast-forward   : disable
bfd                 : global
l2forward           : disable
icmp-redirect       : enable
vlanforward         : enable
stpforward          : disable
ips-sniffer-mode    : disable
ident-accept        : disable
ipmac               : disable
subst               : disable
substitute-dst-mac  : 00:00:00:00:00:00
status              : up
netbios-forward     : disable
wins-ip             : 0.0.0.0
type                : physical
netflow-sampler     : disable
sflow-sampler       : disable
scan-botnet-connections: block
src-check           : enable
sample-rate         : 2000
polling-interval    : 20
sample-direction    : both
explicit-web-proxy  : disable
explicit-ftp-proxy  : disable
tcp-mss             : 0
inbandwidth         : 0
outbandwidth        : 0
spillover-threshold : 0
ingress-spillover-threshold: 0
weight              : 0
external            : disable
devindex            : 4
description         :
alias               : LAN2
l2tp-client         : disable
security-mode       : none
device-identification: enable
device-user-identification: enable
device-identification-active-scan: enable
device-access-list  :
lldp-transmission   : enable
fortiheartbeat      : enable
broadcast-forticlient-discovery: disable
endpoint-compliance : disable
estimated-upstream-bandwidth: 0
estimated-downstream-bandwidth: 0
vrrp-virtual-mac    : disable
vrrp:
role                : lan
snmp-index          : 2
secondary-IP        : disable
auto-auth-extension-device: disable
ap-discover         : enable
ipv6:
    ip6-mode            : delegated
    nd-mode             : basic
    ip6-allowaccess     :
    ip6-reachable-time  : 0
    ip6-retrans-time    : 0
    ip6-hop-limit       : 0
    dhcp6-prefix-delegation: disable
delegated-prefix            : ::/0
preferred-life-time         : 0
valid-life-time     : 0
delegated-DNS1      : ::
delegated-DNS2      : ::
delegated-domain          :
    dhcp6-information-request: disable
    ip6-send-adv        : enable
    ip6-manage-flag     : enable
    ip6-other-flag      : enable
    ip6-max-interval    : 600
    ip6-min-interval    : 198
    ip6-link-mtu        : 0
    ip6-default-life    : 1800
    ip6-upstream-interface: port4
    ip6-subnet          : ::2.0.0.1/120
    ip6-delegated-prefix-list:
        == [ 1 ]
        prefix-id:         1           upstream-interface: port4                    autonomous-flag: enable                    onlink-flag: enable                    subnet: ::2.0.0.0/120
macaddr             : 08:5b:0e:ca:XX:XX
speed               : auto
mtu-override        : disable
wccp                : disable
drop-overlapped-fragment: disable
drop-fragment       : disable


-------------------------------------------------- IPv6 Addresses and Current Ipv6 Routing Table ---------------------------

IP Addresses Allocated by Prefix Delegation

router # diagnose ipv6 address list
dev=3 devname=port1 flag= scope=0 prefix=120 addr=2001:XXX:XXXX:ed3f::100:1 preferred=2211 valid=2211
dev=3 devname=port1 flag=P scope=253 prefix=64 addr=fe80::a5b:eff:feca:XXXX preferred=4294967295 valid=4294967295
dev=4 devname=port2 flag= scope=0 prefix=120 addr=2001:XXX:XXXX:ed3f::200:1 preferred=2211 valid=2211
dev=4 devname=port2 flag=P scope=253 prefix=64 addr=fe80::a5b:eff:feca:XXXX preferred=4294967295 valid=4294967295
dev=6 devname=port4 flag=P scope=253 prefix=64 addr=fe80::a5b:eff:feca:XXXX preferred=4294967295 valid=4294967295
dev=8 devname=root flag=P scope=254 prefix=128 addr=::1 preferred=4294967295 valid=4294967295
dev=10 devname=vsys_ha flag=P scope=254 prefix=128 addr=::1 preferred=4294967295 valid=4294967295
dev=12 devname=vsys_fgfm flag=P scope=254 prefix=128 addr=::1 preferred=4294967295 valid=4294967295
dev=19 devname=ppp1 flag=P scope=253 prefix=10 addr=fe80::a5b:eca:fffe:XXXX preferred=4294967295 valid=4294967295

Current IPv6 Routing Table
router # get router info6 routing-table
IPv6 Routing Table
Codes: K - kernel route, C - connected, S - static, R - RIP, O - OSPF,
       IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       I - IS-IS, B - BGP
       * - candidate default

Timers: Uptime

C       ::1/128 via ::, root, 5d17h03m
C       2001:XXX:XXXX:ed3f::100:0/120 via ::, port1, 05:25:17
C       2001:XXX:XXXX:ed3f::200:0/120 via ::, port2, 05:25:18
C       fe80::/10 via ::, ppp1, 06:27:40
C       fe80::/64 via ::, port4, 3d09h57m
K       ff00::/8 via ::, ppp1, 06:27:52