Disclosure: Breakout EDU is currently an advertiser on FreeTech4Teachers.com
Watching the game design tutorial videos is probably the best first step if you're interested in creating your own Breakout EDU games. Those six videos walk you through the overall concept of game design then the five steps of building and publishing your game.
After watching the game design tutorial videos you'll be ready to build your first Breakout EDU game. All of the templates and artwork that you need to get started are available on this Breakout EDU resources page. The templates are in Google Docs format so that you can quickly copy and save them in your Google Workspace account.
For inspiration for making your own Breakout EDU games take a look at this handful I highlighted last week.