Discover a stunning world of motor sport brought to life, from racing muscle cars through the iconic streets of San Francisco and competing in the legendary 24 hours of Le Mans to drifting around the docks of Yokohama. Jump behind the wheel of exhilarating racing cars in the most aggressive, spectacular wheel-to-wheel races you've ever experienced.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.