Activating the steam key
1) You must download and install Steam from https://store.steampowered.com/about/Steam or https://steamcdn-a.akamaihd.net/client/installer/SteamSetup.exe (if not already installed).
2) Create a new account on Steam or log in to an existing one.
3) Select "Activate a Product on Steam ..." in the "Games" or "Add a Game" section, and enter the key received after payment.
4) After activation the game will appear in your list of games and you can install it.
Please leave feedback after successful activation :)