1. To lock the screen, press the Power/Lock key.
   
2. To unlock, press the Power/Lock key.
   
3. Touch and drag the screen in any direction.
   
4. To enable and use Knock Code, swipe down from the Notifications bar.
   
5. Tap the Settings icon.
   
6. Under the Display tab, tap Lock screen.
   
7. Tap Knock Code.
   
8. Follow the on-screen instructions.
   
9. Tap the code to unlock.
   Note: To learn more about requesting a device unlock for your AT&T mobile device, visit www.att.com/deviceunlock.