Samsung Galaxy Tab A with S Pen (2016, 10.1") 用户手册

Basics

27

Meaning
New text or multimedia message
Alarm activated
Mute mode activated
Vibration mode activated
Flight mode activated
Error occurred or caution required
Battery power level

Pressing the Power key turns off the screen and locks it. Also, the screen turns off and 
automatically locks if the device is not used for a specified period.
The screen is locked with 

Swipe, the default screen lock method.

Press the Power key or the Home key and swipe in any direction to unlock the screen.