bsp file for the map you chose (Steam>SteamApps>common>left 4 dead 2>left4dead2>maps)and extract the “root” folder into the folder you made in the last step.
(so far I’ve only been able to get a few from the Dark Carnival campaign- concert, barn, and fairgrounds- to work correctly) Not all maps will work when imported.
Use GCFScape to extract the file titled “pak01_dir.vpk” into the temporary folder you just made.Create a temporary folder in your documents.Step 2 (aka: the part that also gets the L4D2 prop models into SFM):
Download and unzip the files for GCFScape and BSPSource.This tutorial may be a tad confusing as I had to learn as I went (and I still don’t know all about how exactly this works) and I’m only kinda sub-par at explaining things, but here it goes.