Slide out cover detached roof trim

If memory serves me correct, there is a track that a plastic continuous screw cover will attach to when complete, you will go through that track, the actual roof material and the upper part of the sidewall into an aluminum square tube. I got a couple of the screws started and then started drawing it down tight a little at a time. Caulking in that area may be difficult, you may end up using Butyl tape between the layers for sealing, and then using silicone or another sealer under screw cover. It was over 10 years ago when I fixed mine, but this seems pretty close. Hope this may help, have a great day Bert