Newbie. Aspects of builder to learn for reaction time app?

Main question: a) Think drag race lights. Hold a button, lights start, release and it displays reaction time from the green. If I want to build a mobile app to test reaction time, which of the features, tricks, flows, etc should I focus on learning/using? I’d also like something like a leaderboard and/or various stats.

Bonus question: I’m already in the middle of a decision tree app. Input confidence levels and variables, it displays results/decision suggestion. If I want these on the same mobile app overall (one download, multiple aspects/tools inside), do I have all of these correct:

  1. I should use one page for the decision tree (instead of three for permanent user settings, temporary settings, results)
  2. I should use one page for the reaction time mini-game (instead of three for timer and light sequence settings, lights themselves, and statistics/leaderboard)
  3. I can put as much semi-permanent user-related info for various “sub-apps” in the User data type, and use separate data types for temporary-ish data types for each sub-app.

Thanks everyone. I’m not asking you do it for me (yet) but I do want to know what to focus on. Thanks!