Both side rail guides had broken

I first unscrewed the broken right rail from the back piece and replaced with the new rail. Did the same for the left piece side. Attaching to the front rail was challenging because I took a while to figure out how to remove the cover (where the pictures of the vegetables/fruits are). But if you just get a narrow flat-head screwdriver under there, it just pries off. Then you can get to the little screw that attaches the side rails to the front piece.