Here we will attach the magnets to the frame and side panels. You will use 4 magnets that are 5mm x 5mm cylinder and 4 magnets that are 10mm diameter x 2.5mm thick

Mix some epoxy and put a small amount in the holes on the frame and the holes in the side panels.

First insert the magnets in the frame. Then get the matching side panel for that frame and 2 of the 10mm magnets for the side panel. Make sure the side of the magnet that attracts to the magnet in the frame is the side you see when you put them in the side panel.

Do the same to the other side of the frame and other side panel. Doing it this way makes sure the side panel magnets attract to the magnets in the frame rather than repel each other.