The Walking Dead: Saints & Sinners | GL

Launch the Steam client on your computer and sign in to the account you want to add the game to.

In the top menu, open the "Games" section and select "Activate a Product on Steam…".

Click "Next" and agree to the Steam Subscriber Agreement.

Enter the key you received without spaces and click "Next" — the game will appear in your Steam library; you just need to download it and launch it via your VR headset.

Via browser: open store.steampowered.com/account/registerkey, sign in to your Steam account, enter the key, and confirm activation — the game will be added to your library.