"Mod Menu that unlocks every kind of cheat you might desire in game.achievements , god mode, infinite generator , infinite ammo, etc..."
INSTALLATION TUTORIAL : open the zip file you have downloaded and once you have done it , drag to the desktop (or whatever position you find more comfortable to manage it ) the file "ItemHandler(modded).hps" and rename it  to simply "ItemHandler.hps."

once done, follow the path : Steam/steamapps/common/AmnesiaTheBunker/script/custom/modules  and replace ItemHandler.hps (you don't need to backup the original , because i alread included it in the zip file)

To open the Mod Menu : once you open the inventory in game .just click the icon "100HP" and it will show up.

That's it.
Enjoy folks