Not sure if this is for your exact model but here is a link to an Online User's Manual for one similar:
Just click on the link (underlined and highlighted text) with your mouse and a new browser window will automatically open to show you the information in the manual.
On page 7, it reads as follows:
To Lock Cooktop: Touch and hold the CONTROL LOCK/
ALL OFF keypad for 5 seconds. After 5 seconds, CONTROL
LOCK will glow red, indicating that the cooktop touch controls
are in the lockout position.
To Unlock Cooktop: Touch and hold the CONTROL LOCK/
ALL OFF keypad for 5 seconds.
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