Lenovo TAB3 8 User Manual page 5

Tap
Notifications and Quick Settings
Swipe down from the top of the screen to view system notification messages
and quick settings. By tapping on a switch, you can quickly turn a number of
frequently used functions on or off.
Force shutdown
Press and hold the On/Off button for more than 8 seconds until the screen goes
dark.
to stop running all the apps except the locked ones.