Garry's Mod SRCDS

[Camyo]

I am currently having trouble adding Left 4 Dead 1 + 2 models/materials into my gmod srcds server. I am not exactly sure what to do, have searched it everywhere; to no avail. Not a big deal, it's probably an easy fix, but not if you don't have experience with it already! Thank you all in advance! Oh btw. Osama Bin Laden is dead.