How to redeem game keys

Hi All,

I recently went onto the site or something… And I bought the “season pass” which give me a CD keys and a (lost now) link on how to redeem it!

When I went to redeem it it says “you already have it, can’t redeem it”
Damn I wasted my money! :confused:
Ho well… I did it again and bought “season (2!!!) pass!” and redeemed it!

Well… now I have this spare “game key” and I want to give it to a friend… but how do they use it?
Didn’t keep the link to the site where I can redeem them! :confused:

I think I found it…