The Human Race had advanced to the point where we could travel among the stars, we developed giant automated machines to help us colonise other worlds, but there was a fault in their programming and they turned and attacked. Forcing us to lay a trap to protect Earth and exiling the Human race to stay on Earth once again.
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