Especially for large apps it is highly recommended to think about your app’s design and behaviour before you start developing. There is
a website called app.moqups.com where you can make mockups of your app. The website allows you to create
a prototype with behaviour when you click buttons and it has lots of components. It even supports Material design, iOS design elements,
website elements and very schematic elements. You can also use my pdf below to create a mockup manually. You can draw your components
and think about what your screen should do. This is also useful to keep an overview how and what values are stored in your variables.
An advice from me is also that it’s good to use Screen1 as a splash screen, because that makes it easier to change the order of your