If your "portable" setup is a Steam Deck, the process is slightly different:

Run the game from its executable (e.g., TombRaider.exe ). You may need to change your outfit at the first campfire to see the changes. Method 2: Using the Mod Manager (Recommended)

: Click Run at the bottom of the TexMod window. The game will launch with the selected textures applied. Method 2: Using the Mod Manager (Portable Tools)

Some older mods may require you to downgrade your game to a specific beta build (like Build 811.3) via the Steam properties menu if the modern mod manager doesn't work for you.