Como ativar Steam key
How to activate a game in the Steam Platform!
Step 1. Visit http://store.steampowered.com/about/
Step 2. Press “Install Steam Now”, then run the installer and follow the steps.
Step 3. Login to Steam with your account or create a new one.
Step 4. Press “+ ADD A GAME” on the bottom left of the main window and then “Activate a product on Steam…”
Step 5. Press “Next >”
Step 6. Press “I AGREE”
Step 7. Insert your key into the field and then press “NEXT >”.
Step 8. After a few moments your game will be activated and you will be able to download it.
Step 9. After the download is done, you can go to your “Library” find the game on the left side, select it and press play!
Step 10. Enjoy your game!