How do you extend the socket? I see a clamp but it doesn't seem to work without trying to pry it

Thank you for asking. The socket has a push button on the side, push it to extend the socket until any location you want to stay, then let it go, the Lowes.com also display a video to show you how to find the push button on the socket to adjust the height. Video link: https://www.lowes.com/pd/Screw-in-Multi-Function-Work-Light/5000212445