How to make your own VPK file addon for L4D2?
1. Go to Steam\steamapps\common\left 4 dead 2\left4dead2\addons and create a new folder there. For instance, my example here is ‘All Azunyan’
2. The structure inside the new folder should be the same as inside the ‘left4dead2’ folder.
3. An important thing in your addon folder is ‘addoninfo.txt’
Nothing biggy here since most of the stuffs are for users know that what you’re trying to convey inside your addon. By right, the moment you run you game, you should see your addon in Extras > Add-ons. But it’s not working yet despite you have changed something there. Because you need to pack it up to VPK file but let’s wait for now.
4. Since you wanted to change the sound of your l4d2, look inside Steam\steamapps\common\left 4 dead 2\left4dead2\sound folder.
This is an example of Rochelle (or Yui if you prefer that way) sound folder. Put a new sound file inside your addon sound folder and rename it according to the list in original folder. Coach (Mio) is coach folder. Ellis (Mugi) is mechanic folder. Nick (Ritsu) is gambler folder.
5. After all done (or perhaps you want to try out), while your addon folder window still there, open another window and open Steam\steamapps\common\left 4 dead 2\bin folder. Scroll downward until you see ‘vpk.exe’ file and drag your addon folder onto the exe file. A dos window will pop out and it’s currently packing up your addon VPK file.
6. By now, when you run your game while your add-on is enabled, it should be working according to what you have modded.