Instructions
Turn on your Xbox 360 and sign into your Xbox Live account.
Select "Friends." Invite new friends by clicking "Add new friend" and entering their Gamertag. Press "Enter" when you are done to send a friend request. Upon accepting your request, the friend will appear in your friends list.
Navigate through your friends list to find each friend. A friend&'s availability status is indicated by either "Online" or "Offline."
Press "A" on friends to see their gamer profiles or to invite them to a game session if they are online.