Multiplayer FAIL...

First off, i know that to some, this question is RETARDED, but im not that smart on this stuff so i dont know what the technical crap means.

Its pretty simple, i want to play online with my friend, so i hit Create Multiplayer and started on a CSS map, when he goes to join, it cant connect to my game, why does this happen?

I can’t join my friend’s LAN game/I can’t see servers I’ve made with Create Server.

This requires you to forward some ports on your router. There’s tutorials on how to do this all over the internet, and also