To activate the Steam key you've received, follow the instructions below:
- Open the Steam client. If you don't have it, simply click the "Install Steam" button here: https://store.steampowered.com/about/
- Sign in to your Steam account. If you don't have one, click here to create a new one: https://store.steampowered.com/join/
- Click on the "ADD A GAME" button in the bottom corner of the client.
- Select "Activate a product on Steam..."
- Copy & paste the activation key that you've received from Voidu in the window. You can find the key by clicking on your order number.
- Your game is now visible in your library! Click on your "Library".
- Click on the game and select "Install" to start your download.
That’s it! You can also check the following video for a full activation process demo: