Sign in to your Xbox 360 with your Microsoft account.
Press the 'Xbox Guide' button on your controller.
Select 'Games & Apps' and then 'Redeem Code'.
Enter your unique code that’s displayed on the ‘Order’ page of your CDKeys account or on the link of your confirmation email if you had purchased as a guest and follow the prompts.
Enter your unique code that’s displayed on the ‘Order’ page of your CDKeys account or on the link of your confirmation email if you had purchased as a guest.
Via Xbox Console Companion App (if the web browse doesn’t work for you):
On your PC click the 'Start' button at the bottom left of the screen and select 'Xbox Console Companion' from the apps list.
Make sure you are logged in to the Microsoft account where you would like to redeem your code.
Select 'Microsoft Store' from the left navigation bar then select 'Redeem a code'.
Enter your unique code that’s displayed on the ‘Order’ page of your CDKeys account or on the link of your confirmation email if you had purchased as a guest and follow the prompts to activate.