Help to play in local network

Hello, I cant make work the address_translation.conf to play in my other PC on the same local network.

Suppose that:
Gateway: 192.168.1.1
IP PC1 (server): 192.168.1.10
IP PC2 (to play): 192.168.1.20
Public IP: 190.160.30.4

Game Translations for clients/games (client data ports)
input (ip:port)    output (ip:port)    exclude (ip/netmask)    include (ip/netmask)

How do I have to configure it? Which new port do i have to do forwarding and with which IP?

For external users is working

Sorry my english and I hope you can help me.

Thanks