Flightline Interior

I've got a full interior from Abby and I'm really happy with it. I'm in the process of putting it in and have it all figured out with an exception. The piece that covers the upper baggage bulkhead has 6 or 7 #6 screws and nutplates with the proper finishing pieces. I'm assuming these go around the upper perimeter of this piece but I haven't been able to find a representative picture. I sure would appreciate some guidance on this if anyone has done it successfully.

I also have a package of foam parts that I'm assuming go behind the upper cover between the corrugations on the bulkhead to hold the cover flat.

If anyone has suggestions or pictures, I would appreciate it.

Panel Backing

Can you tell what the backing is made of for the stiff panels. Is it corrugated plastic? I am thinking of making my own for an RV-6 and was wondering what the pros use. Thanks.

It's a hard cardboard.