The instructions found in the the vpk Also use GCFscape

Installation Guide [ENGLISH]

This mod needs to be installed MANUALLY.

Instructions for the installation of the background:

1- Download the mod and leave it on your desktop.
2- Go to the folder "\ Left 4 Dead 2\ left4dead2\ media".
3- Take the files "l4d2_background01,02,03,04,05" and leave them in another folder so as not to lose them.
4- Now we must extract the rar file that they downloaded, when they have extracted it, they will have left a file l4d2_background01.bik
5- To this file l4d2_background01.bik we have to create 5 copies of the file, and change the names of the 5 files to the following:
l4d2_background01
l4d2_background02
l4d2_background03
l4d2_background04
l4d2_background05
6- And when they have these 5 .bik files, they will move it to the following folder "Left 4 Dead 2\ left4dead2\ media"
7- And that would be it, now open the game and enjoy your new background.

►Video Installation Tutorial: https://youtu.be/F4yi2-flGkw


PS: Also use GFCscape: https://gamebanana.com/tools/26