Toilet flange question

I posted a question under the Argosy trailer forum and hoping some of you can answer for me? It's listed as New toilet suggestions.



I need to know if the screws that hold the adapter and flange are simply going through a plywood subfloor or the tank itself?



I assume the tank flange has a bit of a neck to drop down and connect to the actual black tank therefore when I screw it down it will not puncture the tank?



Thanks