Find "Set up screen lock"
Slide your finger down the display starting from the top edge of your phone.
Press the settings icon.
Press Set up screen lock.
You can create several types of phone lock codes. The following steps show two examples:
Create phone lock code using a pattern, go to 2a.
Create phone lock code using a PIN, go to 2b.
2a - Create phone lock code using a pattern
Press and drag a point to connect at least four points.
Repeat the selected phone lock code to confirm.
2b - Create phone lock code using a PIN
Key in the required phone lock code and press Continue.
Key in the phone lock code again and press OK.
Turn off use of phone lock code
Return to the home screen
Press the Home key to return to the home screen.