No matter which interface you are on the screen, you can go back to the main screen by pressing the soft key "Home" on the bottom right corner of the screen.
By pressing the "Back" Soft key you can backup to the previous screen, until you reach the main screen again.
By pressing the "last app" Soft Key, the previously used apps will appear.
You can view the strength of your Wi-Fi connection by viewing this meter.
You can view the remaining battery life on your tablet by viewing this meter.