Re: How to Open RDP on fortigate 40F
you create a virtual IP, which a public IP address on the external side and the IP address of the Windows 10 on the internal side.
use that virtual IP in a firewall policy from external to internal.
you probably only want to allow RDP traffic on the firewall policy
this is assuming that you have a public IP address on the FortiGate. if you haven't that you will have to do the forward on the ISP modem / router towards the FortiGate and then use the virtual IP