Port Forwarding for Steam

[sar90]

Hi all! First port here. I recently got a router (not a good one) in a bundle deal from my ISP. An ethernet cable connects straight to me desktop. Problem is that the moment this new connection came in, I cant connect to any of my multiplayer games on Steam. I'm at a loss. I tried portforwarding but I dont know if I did it right as the games still dont seem to work. Can anyone help me see if im missing something?
And what is the difference between port forwarding and port triggering? my router's homepage seems to have both features, the latter looking very confusing to do. trigger port, open port etc, it all looks greek to me. Any kind soul willing to shed some light on this please?

[LeafyisBeafy]

first of all look if the ports you entered are actually good and if you want to check it go to canyouseeme.com and type the port you used Gmod port is 27015 so you use that at port forwarding and at canyouseeme.com