How do I activate the Panel Lock to prevent accidental changes to the cooktop settings?

To activate the panel lock, the cooktop must first be turned off. Touch the Panel Lock key for approximately 4 seconds until the indicator lights up, confirming the cooktop is locked. To deactivate, turn on the cooktop with the main switch and again touch the Panel Lock key for approximately 4 seconds to release the lock. (Page 21, 30)