Hi all. I’ve bought one of the above and am having trouble with it. The drawer units have a plastic plate attached to the edges of each side of the base and these slide onto the frame. The plates are grooved to fit onto ‘male’ sections. I’m having a terrible time trying to get the plates to slide onto the frame. In fact, I’ve given up and just balance the drawers within the frame. Obviously, they’ll one day slip out! Has anyone got one of these boxes and knows if there’s a knack to it? I’m seriously thinking of resurrecting my old Preston box. ???