VPN DHCP and zero receiving

[Ahmed]

i have Fortugate 200D 

I created client to Site VPN 

How can i use DHCP of Fortigate to obtain IP address 

there is sub interface named VPN under my WAN interface but there is no any DHCP confiuration 

Also after i connect, there is no receiving bytes 

I have Forti OS 5.2.2

any Step By Step configuration 

Thanks All 

[Mark_Oakton]

how have you setup the routing?