VNC over proxy different lans

[xames]

I have proxy installed in opnsense, and i want to connect from LAN1 to LAN2 over vnc, wich rules i have to open, firewall rules only or nat rules?

The client from connection is on opnsense network LAN1 with proxy
The client to connection is on other LAN2 outside opnsense and proxy but connected with cable on LAN2 to opnsense.

Thanks.