How do I install source mod and meta mod for my Left for Dead 2 instance? Some of the gameplay options within my L4D2 instance require source mod. For example, if I want to change the game mode from co-op to survival I believe I would need source mod. Looking at the discord it sounds like the instances should already have these things installed? Do I need to download the files on my own? Down below is the discord thread I am referring to.