Find "Screen lock"
Slide your finger down the display starting from the top edge of your phone.
Press the settings icon.
Press the settings icon.
Press Security.
Press Screen lock.
Change phone lock code
Key in the phone lock code.
Press the required phone lock code.
Follow the instructions on the display to change the phone lock code.
Press the required phone lock code.
Follow the instructions on the display to change the phone lock code.
Return to the home screen
Press the Home key several times to return to the home screen.