Things You'll Need
Instructions
Log onto Xbox Live.
Go to "Game Marketplace" from the dashboard.
Go to "Add-Ons &Extras."
Select "Themes."
Select "Titles A-Z."
Select a letter. For instance, if you want a "Halo: Reach" theme, select "H."
Select an item from the list.
Select a theme from the item's theme list.
Select "Download."