: Open the Steam client on your PC. If you don't have it, download it from the official Steam website .
: Once purchased, go to your Library , select M.A.S.S. Builder , and click the blue Install button.
: Click "Add to Cart" and complete the checkout process for the full version.
To download the full version of for PC, you must purchase the game through official digital storefronts. The game transitioned from Early Access to a full release on September 14, 2025. ⚠️ Safety Warning
: Type "M.A.S.S. Builder" in the store search bar and select the game from the results.