Steam, a computer gaming platform from Valve Corporation, lets players buy, download and play video games. For certain video games, players can buy a CD or DVD of the title in shops. Later, they can activate it on Steam using the CD key, or code, which can be found inside the game's packaging. Activating a game on Steam lets users re-download the game at a later time and also provides players with additional features, such as automatic updates or an integration with the Steam Community network. You can activate your code on Steam in just a few steps.
Visit the "Retail CD Keys" page on Valve's website to check if your game is eligible for Steam activation (see Resources).
Launch and log in to the Steam application.
Click on the "Games" menu at the top of the window, then select the "Activate a product on Steam" option.
Click on "Next." Read the terms and conditions and click on "I agree."
Type the CD key, or code, and click on "Next." You can usually find the CD key on the CD or DVD or on a sticker inside your video game's box.
Click "Finish." Your game will now appear in your Steam library.