You can add a fourth navigation button to make it easier to turn the display off, toggle auto-rotate, and more. 
	 
 
  
 
	 -  
		  From the 
				Home screen, tap 
				. 
			  
		
-  
		  Tap 
			 Change navigation buttons. 
		   
		
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		   Tap a fourth navigation button to add it. 
		   
		  To have only three navigation buttons, make sure none of the fourth button options are selected. 
		   
		
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		  Tap 
			 Done to save and apply your customization.