Instructions
Scroll down to "Team Management" and press "A."
Scroll to "Roster Share" and press "A."
Scroll to "Download Roster" and press "A."
Enter the gamertag of the person from whom you want to download a roster. Use the on-screen keyboard to enter the characters. You do not have to be friends with the gamer to download the roster.
Scroll to "Enter" and press "A." The downloadable rosters from the gamertag you entered will be displayed.
Scroll to the roster you want to download. It should be highlighted. Press "A" to download it to your hard drive.
Press "Y" to return to the main menu.
Scroll down to "File Management" and press "A."
Scroll down to "Load" and press "A."
Scroll to the downloaded roster and press "A" to load it to your game.