1. Find your dedicated PC on router.
2. Set static IP to DCHP (by MAC).
3. Set it up as your LAN's object.
4. Make protocols:
Name: FOnline Server //example name
TCP Any -> 4040 //updater's port
UDP Any -> 4040 //as above
TCP Any-> 2238 //game server's port
UDP Any-> 2238
TCP Any -> 80 //for vtdb (if you want to use it, by http server with php)
Name: Remote Desktop //if needed
TCP Any -> 3389
UDP Any -> 3389
Name: FTP //if needed
TCP Any -> 21
And idk, TS3: //just a curiosity for different port config
Name: TeamSpeak 3 Server
UDP Any -> 9987-9997 //port range here!
TCP Any -> 10011
TCP Any -> 30033
And maybe, Wake on LAN: //another curiosity, works with forwarding
Name: WoL //or Wake on LAN, or WoLAN, or whatever
UDP Any -> 9
5. Forwarding...
Sign those protocols to your LAN object!
6. Reboot your router device
Good luck!
PS
Please tell us your router model next time - it will be really easier with proper documentation!