M300 mini smart router Vpn

I have two different network and I would like to connect them to each other through a server VPN as you can see in the image attached.
I bought a 300M Mini Smart Router of Gl iNet to do it. This router is connected to internet through the WAN port. The VPN server is installed on a VPS with public IP.
I set the VPN client part of the router but I have an issue: I see the router in the VPN but I can’t see any devices linked to the router.
I think that I have to set a router table but I don’t know how to do it.
Have you a guide or a documentation that could help me, please?
Thank you

I do not have guide for openvpn. You may need to do some static routing. Or simply use port forward.

We have such settings using wireguard. Pls check. You need to have two routers and use cloud to manage them, link two subnets.