Why do it yourself? I’ll let one of my colleagues make this point: “I should have remembered the horrible experience with John Wiley publishers 20 years earlier, long before self-publishing was even an acceptable option. I ghost wrote a business and health book. We fought with the editors about the title (they won). We fought with the designers about the cover design (it’s still ugly). And we were disappointed when the book didn’t sell. Nobody told us the publisher does so very little to promote it. We were our own best customers. It was ridiculous. We were paying for our books, and the publisher was returning a small share of that back to us in royalties. Dumb me. I was a ‘with’ author on another book 20 years later and ended up on the same path with that publisher.”
In the past decade, the DIY (do it yourself) publishing industry has added Print on Demand (POD) or "Self Publishing" houses to the model of self publishing. You add your book to their listings, you pay them to publish it, and they bring it into their distribution set up. This publishing method is not addressed at length here, but please understand what these companies are and how they work before getting into a deal with them. This type of publishing is a good deal for poetry, memoirs, and fiction, but NOT the best model for nonfiction with authors who have a “platform” on which to speak outside of book signings and other events related to the book alone.
Do it yourself, but hire qualified professionals to help you along the way.