Publishing a book is all about book design. All you really need to publish is a formatted book that’s professionally laid out for print, with smart font choices that match your genre or subject. Then you can convert your manuscript in ebook formats (epub and mobi) – I even have a free ebook conversion tool.
Next you’ll need a Kindle ebook cover (about 1600 x 2700 pixels, which equals 6″x9″ @300dpi).
If you don’t have photoshop, you can get a cheap cover on Fiverr (which aren’t great) or use my free book cover design templates to make your own.
That’s enough to set up on KDP for the Kindle version – you could also use Draft2Digital to distribute your ebook (though I prefer Kindle Unlimited’s Select program). Print books are more complicated, because you need to calculate the spine width based on page count, and get the trim right, and it has to be precise or Amazon will reject the files (Createspace is more forgiving if you skip the automatic previewer. KDP print is picky).
Upload your files, congrats, you’re published!