Firefighting Simulator - The Squad | GL

Launch the Steam client and sign in to your account.

In the top menu of the client, open the "Games" section.

Select "Activate a Product on Steam…".

Enter the key from the email and follow the on-screen prompts — the game will appear in your Steam library.

Via browser: open the page store.steampowered.com/account/registerkey and sign in to your Steam account.

Enter the key in the field on the page and confirm activation — the game will be linked to your account and available in your library.