There are two little pins on the front of each of the roof panels that fit into two holes in the windshield frame. On mine, the drivers side pins weren't lined up and it wouldn't fit until I gently adjusted them. To fit the panels, you have to insert the front pins first and then push down gently on the rear of the panel to seat it. If the pins in front are slightly bent, the panel won't go in. You have to gently fiddle with the pin(s) to get them straight so they will insert properly. I stress being gentle because the pins can easily break off. Also, the distance between the windshield frame and rear roof frame wasn't consistent between drivers side and passenger side (driver side was tighter) so I had to insert the driver side panel first and then the passenger side.