For the textures to work properly please follow these steps:

1. Place the houseofcards.vpk in your L4D2 addons folder
   (Steam/SteamApps/common/Left 4 Dead 2/left4dead2/addons)

2. Go to your L4D2 materials folder which can be found via 
   Steam/SteamApps/common/Left 4 Dead 2/left4dead2/materials
   and place the folder "custom" into it.

3. Launch your game, create an online lobby, in the server options
   select "Local Server" and invite your friends.

4. Play.

