can anyone help me on DLing Skyrim exp packs?

[steelerguy52]

a few weeks ago I purchased skyrim and the 2 expansion packs from Game stop. I downloaded the main game but am having a problem with the exp packs. GS says dl steam and register an account,,,did all that, then they say to hit games tab and select Activate game code, well I cant figure out how to do that because there is no activate game code or anything.