Hey guys, I recently set up my gaming rig and tried to set up my Elder Scrolls Anthology, but I can't seem to remember how I set up Oblivion's Steam version so I could get the DLCs. Same goes for Morrowind. I've tried looking this up but can't find any good tips. Any advice? I have my Steam key right in front of me, and I've already installed all of the Anthology, but I can't recall how to use the Steam key.

Thanks for any responses guys.