Things You'll Need
Instructions
Turn on the game and choose the Xbox Live option from the main menu that will pop up when the game loads.
Select "Bonus Content" from the Xbox Live menu options. A list of map packs that are available for download with appear on the screen.
Choose the map pack to see an in-depth description of what is included in the purchase. If you don't see a map specifically listed as "zombie," press the "B" button on your controller to choose another map pack.
Fill in your credit card and personal information once you have found a map pack that includes a zombie map and have selected it for purchase.
Select the "Purchase" button to start the map pack download. Once your download is complete, you can play your new zombie levels the same way you would the original levels.