Well here are the steps you must follow
1) Go buy an HDMI cord (if you already have one then GREAT)
2) Make sure your TV is an HD TV
3) Plug the HDMI cord into the Xbox and the TV
4) Make sure that all of the people who want to play have there Xbox remote on and signed into an account
5) Once you go into the game with player 1 make sure all the other players who want to play double press start
6) Comment and diamond!