In that same 'More' menu that the player selected earlier, they will now see an option for 'Open Mods Menu'. With this done the player will now be able to access the game's folder for modding things. This will need to be selected in order to open up a menu where the player can then select a button that says 'Enable Mods'. Once here they will see that there is a 'More' button underneath the 'Play' button. In order to begin using mods players will first need to go into the Xbox app on their device and go to Fallout 4's home page. Players also may not be able to use any modding tools with the Game Pass versions either unless those tools have been specifically updated for that version of the game.
The trick to this is to only download and install mods that don't use script extenders or replace files entirely. There are still quite a few mods out there that will work with Game Pass though. The Xbox app prevents players from editing certain file types, which means that several popular script extenders and visual mods will not work correctly with this version of Fallout 4.
Unlike modding a game that was bought on Steam or GOG, using a game through Game Pass means that it comes with certain restrictions. Before players just jump right in and start trying to install every mod they see they will want to keep in mind that this process isn't as simple as it may look on the surface level.