The navigation buttons appear at the bottom of your screen. You can tap 
, 
, or 
to get to the previous screen, the home screen, or to see recently opened apps and screens.
The three navigation buttons are Back button , Home button , and Recent button .
The Back button opens the previous screen. For example, in the Chrome browser, when you tap this button, the browser displays the previous webpage. If the touch screen keyboard is opened, when you tap the button, the touch screen keyboard is hidden.
The Home button opens the home screen.
The Recent button opens a screen that shows you the apps and screens that you have opened. The Recent button is helpful for quickly switching between different open applications.