Manipulation of 3D/STP files of a prototype product part to show how it works

Information for the business: Product Manufacturer and Distributer
Design details: I have designed a new part to fit on an existing product and I need to see accurate and close up multi angle visuals in 3D to check it fits and works as expected before I proceed to tooling.

The existing product is a folding plastic box made from a 1mm plastic sheet.

The new product is a rail that covers the open edge of the box to give it rigidity.

The new rail will be made via injection molding in a flexible material - it will be molded flat and then folded over the edge of the box and fixed into place - it is how it sits over the existing box when folded that I need to see.

There is one particular area of concern which is at the end of the rail where it is at a 45 degree angle - I need to check that the fit is flush and there are no obvious sharp edges.

I have PDF and STP files of the flat sheet for the box - these will need manipulating into the box shape - these files show the exact dimensions and also the positions of the holes which are used to locate the folding rail in the correct position on the side of the box .

I also have PDF and STP files of the folding rail - this rail will need to be shown folded over the box and fixed into place with close ups of one of the 45 degree ends from outside, top and inside.

I also have a PDF file which shows the flat sheet made into the box with the rails located into there fixing holes - very nearly what I need! What this file doesn't show and what I need, is to see the rails folded over into place and a close up of the 45 degree tips from the outside, inside and top.

I have a STP file viewer but limited knowledge using it - STP is the final file format preferred however I will also require JPEG or PDF static images of close ups required for ease of printing and viewing.
Ideas for the visual style: See above
Extra notes: I have 14 files available that are listed below - PPH will only let me upload 3 and no STP.

1.) Basic Box Construction - this shows how the sheet folds into the box and where the rails sit before folding over.
2.) Flat Sheet - PDF of flat sheet that makes the Box
3.) Flat Sheet 3D - STP file of flat sheet
4.) Outside Without Rail 1 - this photo shows the area of concern without rails and how the edge of the flat sheet folds over double.
5.) Outside Without Rail 2 - photo with wider shot of area covered by rail - please note this photo does not show the fixing holes that are on the PDF/STP files as these have been added to more recent stock.
6.) Top Without Rail - This photo show top view of the edge to be covered with the rail.
7.) Inside Without Rail - This photo shows inside view of edge to be covered by the rail.
8.) Left Rail - PDF of new design left rail.
9.) Left Rail 3D - STP file of new design left rail.
10.) Right Rail - PDF of new design right rail.
11.) Right Rail 3D - STP file of new design right rail.
12.) Close Up Outside - this is what I need to see to check the design works!
13.) Close up Top - this is what I need to see to check the design works!
14.) Close Up Inside - this is what I need to see to check the design works!

Please contact me if you have any questions or anything is unclear.

Thanks

Matt