Wave of Darkness invites you to a huge dark and gritty fantasy world which can be explored the way you want and whenever you want. The world of Narr is corrupted by the mysterious and bloodthirsty cults, and you will have to do your best to free land from this malicious deviance.
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