Port forwarding problems, need some aid.

I’ve looked all over trying to find a tutorial on how to port forward so I could host a dedicated Garry’s mod server but, my port forwarding page seems a lot different then anyone else.
(I think the modem is a ZyXEL PK5001Z)
This is what my port forwarding page is;

enter your local computer’s IP (ex

ports should be 27005-27020 UDP (off my head)
remote port should stay at all ip addresses

also make sure your firewall is configured the same

Thanks, a friend told me how to solve it, same steps. Local address and ports 27005 and 27015. Thanks though!