One great way to learn the publishing process is to go through a small but reliable press that does the graphic design, line editing, etc and splits royalties. I did this early on with a small but reputable fiction publisher. I have helped clients publish their books, but they’re busy professionals and I ghostwrote, etc.
My fiction writing partner and I are self-publishing our 5th novel … we have a graphic artist … Beta readers … a formatter but do much of the rest ourselves.
Certainly “vanity” publishers or author services are out of the question.