Big Brother Butter is all on the Steam client. The steps are as follows:

1. Start the Steam client on the computer system.

2. Then enter the main steam interface and click the store button to enter the store interface.

3. Then search for houseparty in the search bar on the left.

4. Then enter your personal birthday in the pop-up prompt interface, and then click to view the page.

5. Click Add to Cart on the game purchase interface, and then pay.

6. Then go to your personal library to find the purchased game, install it, and play happily.