Battlefield 3 - Back to Karkand DLC Pack [Online Game Code]

This review is from: Battlefield 3 - Back to Karkand DLC Pack [Online Game Code] (Software Download)

Code-in-a-box and 3rd Party method:

Open the Origin client on your PC, and click Redeem Product Code, under the Settings menu (gear icon).
Enter your code then hit Next.
Confirm that the code is for Back to Karkand and hit Next again.
You will receive a confirmation of your code redemption.
You will now need to go to My Games and update Battlefield 3 to play Back to Karkand.

For me, I didn't have to update anything in my game once I activated the game. (Karkand may have come with that 4GB patch release a while ago.) Anyway, I just started a game, and joined a Karkand map. Truth be told, I too was confused as to how to activate the game until I came across a post by EA. I hope this helps.