by Lucidinferno » Tue Dec 08, 2015 2:04 pm
Sign in to your profile, start up DI, go to the level you want to multiplay in, press the home, or the menu button (the lit-up X in the middle of the controller), go to your profile on the left on the Xbox home screen. Under your profile pic is a two-player icon. Go to that, and you'll see a list of your friends. Go to the one you want to play with (a green dot next to their profile pic means their online), click on their profile, then click on invite, and then invite to game.
Let me know if it works.