Easy Enable Mods Script
Locate your Fallout 4 Preferences folderThis is usually located at C:\Users\YOUR_USER_NAME\Documents\My Games\Fallout4\
Copy the enable-mods.bat script to the Fallout4 folder located in Step 1.
Run the script.
If all went well the script made a backup of your current preferences in a file called Fallout4Prefs.bak, added the correct line to the Fallout4Prefs.ini, and made the appropriate Fallout4Custom.ini file and added the proper lines to it.
Sometimes if you have already attempted to enable mods in the past this will cause problems with this script as it is intended to be run on the default files that are made after the first run of the game.
You can get these settings restored by deleting the Fallout4Prefs.ini, Fallout4Custom.ini, and loading a save then quitting the game.
If you continue to have any problems with the script remove the files: Fallout4Custom.ini and Fallout4Prefs.ini then restore your preferences by renaming Fallout4Prefs.bak to Fallout4Prefs.ini
Consider trying the manual method located here or submit a comment or an issue on the github page.