Deep in the twilight of the Black Forest, you and your companions crouch before the robber-knight's tower. Hans, the alchemist, places his mysterious potion by the door. Ebhard the friar implores Saint Dunstan to bless your weapons and armor. And you and Gretchen grip naked long swords, praying your plate mail won't squeak.
Open the Steam client, login and locate the Games tab on the top menu. Click this and then select “Activate a Product on Steam…”
Enter your unique code that's displayed on the 'Orders' page of CDKeys.com and follow the prompts to activate.
Your game is now viewable in the “Library” tab and is available to download/install when you’re ready. You can find additional support for the Steam client here: https://help.steampowered.com/en/wizard/HelpWithSteam