Hotop Threaded Knurled Thumbscrew Monitor Mount Screws on Knobs Monitor Screws Carbon Steel Clamping Knobs Grip Thumb Screw Mounting Thumb Screw, Black(10 Pieces,M4 x 10 mm)

L-brackets example - you'll need to find ones with holes that match your panel or drill new holes. https://a.co/d/08rYSECH Thumb screws example - just make sure you get the correct size. If you're not sure, take the panel with you to a home improvement store. Somebody will help you figure it out. https://a.co/d/0hK0TjW4