After purchase, you automatically receive a key to activate Enter the Gungeon - Cobalt Hammer DLC without regional restrictions.
1. You must download and install Steam http://store.steampowered.com/ (if not already installed)
2. Register a new account on Steam or go to an existing one.
3. Go to "My Games" and select "Activate via Steam", enter the key.
4. The game after activation appears in the list of games and you can download it from Steam.
5. Enjoy the game.