VLAN to LAN

Hi

I'm using fortigate 60e, version 7.0.1

Network Topology: ISP --> WAN 1-Fortigate Fortigate-Internal --> Switch

My configuration is this

Internal Interface ---

Type: Hardware Switch Interface member: Internal 1

Role: LAN

IP Range: 10.10.10.1-255

Internal Sub Interface ---

Name: Floor2_Staff Type: VLAN

Interface: Internal VLAN: 10 Role: LAN IP Range: 10.10.20.1-255

Policy for staff

Incoming Interface: Floor2_Staff

Outgoing Interface: WAN1

the rest is All

Made this policy so staff can have Internet. Now the next step is I want the Floor2_Staff with ip of 10.10.20.1-255 to access the server on internal which is 10.10.10.2 (and only this server only) Is this possible? and what step should I do? sorry I'm just new with this fortinet.