Trunk floor pan question

[mrr1999]

I'm replacing the trunk floor in my 69 camaro for the first time and I have a question regarding the replacement panels (which may sound really stupid, but I'll ask it anyway). I have the center section and one extension panel for each side that attaches to the drop-downs.

Does anybody know if the center section sits on top of the extension panels or do the extensions sit on top of the center section? I searched around and couldn't find any articles or videos going over this. If somebody knows of a good article covering the install and how everything fits together, that would be great. Thanks for your help.