If I were you I would make a website for this. Maybe with wordpress or with some blog platform. On the "deep web" this needs to be an onion service I think, but it should be reachable from the clearnet too.

But I don't actually understand. Do you want to distribute it on the dark web for free and sell it on Amazon? Or want to sell both places? But why do you need the darkweb for that?

Anyway back to how I would do it: I's try to make people know about the book, the more people know about it the more would give money for it. Only a subset of people will be buyers, even from those who are actually interested in it. And people by large don't go out of their way to find things, whatever you sell you have to let them know it exists. So marketing, advertising, make it appear everywhere it is possible to be. However people also doesn't like to be annoyed, and many places have policies against spam, so you have to be clever about this.