If I had to make an educated guess, I could try to write a general essay about file sharing, data compression, or digital storage, but I'd much rather have a better understanding of what you're looking for.
If you want, I can:
Verify Filenames: The filenames must be identical except for the part numbers. If any part has a suffix like (1) from a duplicate download, rename it to match the original sequence. SONE-206-u.part03.rar
Gather All Parts: Ensure all files (from part01 to the final part) are in the same folder. If I had to make an educated guess,