You have 3 options.

1.) If you do NOT use Snakebite Mod Manager:
open the "Non-Snakebite Users" folder. drop the folder's files into "\Program Files (x86)\Steam\steamapps\common\MGS_TPP\master\0\" (requires steam patch 1.006/game ver 1.02+)

2.) If you DO use Snakebite Mod Manager:
open the "Snakebite Users" folder. drop the folder's files into "\Program Files (x86)\Steam\steamapps\common\MGS_TPP\master\0\" (requires steam patch 1.006/game ver 1.02+)

3.) You use Snakebite Mod Manager AND Infinite Heaven:
open the "Infinite Heaven Users" folder. drop the folder's file into "\Program Files (x86)\Steam\steamapps\common\MGS_TPP\mod\modules\" (requires Infinite Heaven r198+)