How to activate Skulls?

So guys I have been playing Halo CEA and I have picked up some skulls. The skull menu for CEA does not update with the skulls I pick up. For example I have picked up the Boom Skull, but I can not find any way to turn it on so far. Anyone else having this issue? Or are pick up skulls just not a part of the game?

Been seeing that there are a lot of launch issues with the MCC so I was just wondering if this is another thing to add to the bug list.

Am I missing something in the UI?