Scroll down until you find a section marked. Step 2: Open the 'Fallout4Prefs.ini' file using Notepad.Step 1: Go to your documents folder, click your My Games folder, and then open the Fallout 4 folder.This can be done by altering a couple of lines in the game's configuration(.ini) files, which you can find and change by following the three simple steps below. In order to activate mods, you need to enable your game's ability to use them first.