Sliding those panels right in! It is actually 2 panels, the deepest I could get was 3 inches so each section has a 3 in panel and a 1 1/2 inch panel as well!
Now all the panels are in except for the little tiny ones around the top and bottom of the skylight. The first two actual white ceiling panels are up too! There will be a central cross piece and a top and bottom piece to secure them in place.
They are super light corrugated plastic, so they even have a bit of insulating power themselves! Ordered them from Home Depot on line because they are not available in stores and I really prefer this way as they arrived in immaculate condition:)
I will find out how much that insulation helps tonight when it drops into the 30's again.
It actually got hot enough today while I was working, I had to open the skylight to let out some heat!