I'm guessing your question about "parts" is about the what the extra feet do. The feet do the same thing on all that era of sewing machines. Download the manual for a Singer
15-91 and it will tell you what the parts are for. They usually include a foot for sewing a zipper, doing a rolled hem, etc.
bkay
edit: The 15-91 manual is just a more detailed manual. There are several differences in your machine and the 15-91, but the feet still do the same thing.