MeDiC89

If you still have not figured it out.... here are the steps.(granted both of you have active xbox live) Main Menu > Multiplayer > Xbox Live > Play Game > Sign In/Identity Set Up > Player Match > From here you can search for a game that is already created or you can create your own. To join a game go to Custom Match > Mode: Campaign then hit 'A' to search for games. To create your own game, go to Create Public Match or Create Private Match. From there you can select Campaign for the mode and set up which ever mission you want.