This might help Building Apps with Many Screens
How you change screens depends on what your app does. You can use Screens or virtual screens.
If you use Screens, you should use a TinyDB to transfer variables from one Screen to another. Use a virtual screen (described in the link above) and you do not have to worry as all the variables are immediately available to the app.
This describes an old Screen changing recommendation (that works but has the ability to cause problems transferring information between screens). Its saving grace is that it is simple (but might cause your app to suddenly become complex as you transfer information between Screens).
This topic is also discussed here showing an elegant way to switch regular Screens … How do you change from one screen to another with a button?
Regards,
Steve