1. To lock the device screen with a numeric PIN, from the Start screen, swipe in from the right edge of the screen to access the Charm bar.
   
2. Tap Settings.
   
3. Tap Change PC settings.
   
4. Tap Accounts.
   
5. Tap Sign-in options.
   
6. Under PIN, tap Add.
   
7. Enter your current password and OK.
   
8. Enter the Desired PIN.
   
9. Confirm the PIN and tap Finish.
   
10. To lock the device, press the Power button at the top of the device.
    
11. To unlock the device, press the Power button at the top of the device.
    
12. Swipe up from the lock screen.
    
13. Enter the PIN to unlock the device.
    
14. To change your PIN, from the Sign-in options menu, tap Change.
    
15. Enter your old PIN and tap OK.
    
16. Enter your Desired PIN.
    
17. Re-enter to confirm your New PIN.
    Note: To learn more about requesting a device unlock for your AT&T mobile device, visit www.att.com/deviceunlock. If your device is locked and is requesting a "PUK" code, click here for instructions on how to obtain your PUK or PUK2 code to unlock your SIM card.