1. To lock the device, press the Power/Lock key.
   
2. To unlock the device, press the Power/Lock key.
   
3. Swipe up to unlock the device.
   
4. To change the screen lock, from the home screen, swipe down from the notification bar.
   
5. Tap ALL SETTINGS.
   
6. Tap lock screen.
   
7. Tap the Password switch.
   
8. Enter and confirm the desired password, then tap done.
   
9. To change the password screen lock time, tap the Require a password after field.