Gently separate the trays by pulling them apart and levering their sides open. Be careful not to damage the tray at this point.
Attach the end plates to the ends of the core tray body. The body must fit firmly against the back of end plate. This is important to ensure a firm core tray.
Invert the core tray and drill out the blind rivet holes in the end plates. Then insert pop rivets into the holes and secure these using a pop rivet gun.
Attach core tray handles by inserting them into marked slots at either end.