To get access to the tester builds, join Discord and either 1. Donate $10 or more to get test builds forever, 2. Boost the server (Tester lasts for as long as you are boosting the server), or 3. Create videos and link the Discord server as well as this page for the game. The videos can be full-fledged or shorts; just make sure to link the Discord and the itch page. I believe you can make videos once per month and keep tester that way.