1. From the home screen, swipe down from the top of the screen to access the Notification menu.
   
2. Tap the Settings icon.
   
3. Under System, tap Security.
   
4. Tap Screen lock.
   
5. Tap PIN.
   
6. Enter the desired PIN, then tap Continue. Follow the prompts to confirm.
   
7. To unlock the screen with a PIN, enter the required PIN, then tap OK.
   
8. To change the security screen lock type, from the Security screen, tap Screen lock.
   
9. Tap the PIN field, then enter the current PIN.
   
10. Tap the desired security screen lock type, then follow any prompts.