1. Copy the product key
Select the product key and copy it to the clipboard (press Ctrl+C).
2. Run the game
If you already have the game installed simply run your copy from the desktop.
Otherwise download the installer from the official site and run it.
The installer will automatically start the game for you.
3. Activate the game
Wait for the activation screen to appear.
Press Ctrl+V key combination to paste the product key.
Press the Activate Game button to finish the activation.