Prepare yourself for the grim, dark future of the 41st millennium, where alien races battle mankind for galactic domination in a universe of unending war. Personalize your armies with a revolutionary unit customization tool that gives you the ability to choose your armies insignias, banners, squad colors and names.Go to: http://store.steampowered.com/ and download STEAM client
Click “Install Steam” (from the upper right corner)
Install and start application, login with your Account name and Password (create one if you don’t have).
Please follow these instructions to activate a new retail purchase on Steam:
Launch Steam and log into your Steam account.
Click the Games Menu.
Choose Activate a Product on Steam…
Follow the onscreen instructions to complete the process.
After successful code verification go to the “MY GAMES” tab and start downloading.