How can mastering a kivy project?

[tima Help]

We developing a project with kivy. In this project we use kivy_graden routing system. Now we have to need mastering this project like top and bottom bar are fixed there and all other content change dynamically in the middle of the main,kv. How could we achieve this? 

[Alexander Taylor]

Usually you would want to use a ScreenManager to manage content changing between several primary options.