Hello,

Follow those instructions to install the mode :

Extract SK_Res folder to the main folder of the game
steamapps\common\Shadow of the Tomb Raider

To make the mode work you need to have installed SK_FFXV tool first in the game main folder !
steamapps\common\Shadow of the Tomb Raider

Big thx to Apzurv for telling where to get the tool and how to extract textures !!!