If you have pre-ordered the Limited Edition, you just need to update Battlefield 3 through Origin and the Back to Karkand content will be unlocked in your game.  It will not show up as a separate file download on your Direct2Drive account.

Here's how to update through EA Origin:

  1. Open the Origin client on your PC 
  2. Open the Store tab. 
  3. You will now need to go to My Games and update Battlefield 3 to play Back to Karkand. 


If you did not preorder but purchased on GameFly:

  • Open Origin and click on Redeem Product Codes.  Enter your code to redeem the DLC.


For any technical support or key/activation support please see the experts at EA Games Support: http://support.ea.com