A:Answer Dave, thanks for your question. A clamp mechanism is attached to the arms of the tray. A phillips screwdriver is used to adjust and/or remove the shelf. In the manual, it's steps 5.4 & 5.5 on page 8, which can be accessed from the MTMA55PL page on our website. If you have any other questions, feel free to get in contact with us directly by visiting the support page on our website. Cheers!