Rush for Glory is featuring challenging and rewarding Tower Defense battles, in which players are defending their base against an alien invasion. By strategically building towers and upgrading them, the player can keep his base safely and further progress through the extensive singleplayer campaign.
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