In order to achieve it, please follow the steps below:

Launch Steam and log into your account.

On the bottom left, click ADD A GAME

Select Activate a Product on Steam 

Click NEXT then I AGREE

Insert your Product Code and then click NEXT

From your LIBRARY tab you can see all games registered to your Steam account. 

You can then select a game and it will bring up a splash page with a large INSTALL button you can click on to install your games.  Once your games are installed, the Install button will change to a PLAY button!

Send a ticket to our Support Team. Let us know the steps you've already taken, and we'll be happy to help!