Find "Passcode Lock"
Select one of the following options:
Turn on lock code, go to 2a.
Turn off lock code, go to 2b.
2a - Turn on lock code
Key in a lock code of your own choice.
Key in the same lock code again.
Press Immediately or the required interval.
Press Passcode Lock to go back to the settings.
2b - Turn off lock code
Return to the home screen
Press the Home key to return to the home screen.