Click Handler?

Can anyone tell me how to set a “click handler” of a component? I don’t see any such attribute in the component’s Paramater’s tab.

Here’s the tutorial text that references it:
“To add the button for recording, drag a push button from the Components panel onto the Stage, placing it below the Live_video video object. In the Property inspector, give it the instance name Record_btn, the label Record, and the click handler doRecord.”

It’s the last words of the above paragraph that have me scratching my head.