Great difficulty opening object files and fbx files in CS5

Hello, everyone.  I have downloaded some 3d assets from vendors on Artstation but I am having great difficulty opening them.  They are RAR files, fbx files and Blender files.  The Blender files are not a problem.  When I try to convert to .obj and open in PS it says it is not the right kind of file.  Even the RAR files will not open after being unzipped.  Now, I suspect it is because my CS5 is not the extended version and does not include a 3D menu.  Nowhere have I read or seen has mentioned that is actually the problem.  I am hoping that I am wrong and I am missing something.  If anyone can offer a suggestion or work around (if that is even possible) that would be greatly appreciated.  Anything short of having to purchase a CC subscription.  CS5 has served me well for a long time.

[subject edited by moderator to include "CS5" for clarity]