You can extract files to where left4dead2.exe is located doesnt have to go into any special bin folder or anything.
Also make sure to disable ingame Anti-alias(AA) completely it will disable SweetFX from functioning.
You may force normal AA via your GPU's control panel but not recommended seeing your injecting the most efficient and best visual AA method possible, SMAA.
Maken's v1 is the best one that I've used. Followed by K-putt'e Config
ops
too dark