AFAIK concerto is a C library and you need to compile that first. There should be an inerface unit included that links the o file, not a TPU file.
I can't remember if I ever tried to compile it for 32 bit. It is very old software written for 16 bit DOS, so you may need to use FPC for i8086. Your luck may vary.
It is probably not an easy task.....even for advanced programmers. But if the C code compiles for 32 bit you are in luck.