Find "Passcode Lock"
Press Settings.

Press General.

Press Passcode Lock.

Select option
Select one of the following options:
Turn on lock code, go to 2a.
Turn off lock code, go to 2b.
Turn on lock code, go to 2a.
Turn off lock code, go to 2b.

2a - Turn on lock code
Press Turn Passcode On.
Key in a lock code of your own choice.
Key in the same lock code again.
Key in a lock code of your own choice.
Key in the same lock code again.

Press Require Passcode.

Press Immediately or the required interval.

2b - Turn off lock code
Press Turn Passcode Off.
Key in the lock code.
Key in the lock code.

Exit
Press the Home key to return to standby mode.
