Using Amazon's KDP Paperback Publishing System - Some Tips
Yesterday, I helped my wife publish the paperback version of her novel, using Amazon's KDP system, which has replaced CreateSpace for Amazon's print-on-demand book publishing. She had already published the Kindle version, with little technical help from me, but was stymied by the paperback publishing process.
It's actually fairly easy, but is far from intuitive, once you get into the depths of the publishing process. Here are some tips to follow to smooth the process. At every step, you'll find links to help files for each step. Use them. The help is good, and you'll probably need some of it if this is your first time.
1. Amazon won't let you use the converted book content from your Kindle version. Instead, it wants either a printer-ready pdf file or a Microsoft Word document. Here's the trick: You need to format the Microsoft Word document to match the trim size of your published book. To do that, use the Layout tab in Word to set the page size and margins. More on margins later. Once you do that, Word will automatically repaginate and flow the text into that layout. You need to step through the entire document to make sure it looks right, even if you have proofread and checked carefully in another format. Also, the font you choose is the one that will be used in the final printing, so choose it carefully. Use one of the standard fonts available in Microsoft Word and you won't cause an error. Again, check the entire book for layout issues, etc., and adjust appropriately. Use Word Page Breaks between chapters. Want page numbers in your published book? Use Word's page numbering process, or they won't appear in the book.
2. The problem in the step above is in choosing the trim size for your book. You'll have to do that, and then reformat your Word document before uploading it. That's out of sequence in the publishing process on the KDP site. You will absolutely have to choose a trim size so you can properly set Word's page size and margins.
3. Margins. You have to set up margins to include gutter margins. You'll find that setting in Word's Layout dialog box, too. The gutter margin needs to be set according to the trim size and number of pages in the printed version. You can find those specifications in the KDP site at the location for choosing the trim size for your book. The other margins can be set to whatever you wish, from .25" to larger, if you wish. There's a help screen in the KDP app that will give you all the information you need with gutters and margins.
4. The Book Cover. You have two choices. One is free. The other is far from free. You can create a print-ready pdf file to strict specifications. That's hard and expensive. Or, you can use the KDP Cover Creator. You already created a cover design for the Kindle version, most likely. You can use that for the front cover, if you choose. The size of your JPG image, however, is crucial. The Kindle process prints at 300 dpi, so your image has to match the book's trim size at that resolution. For the popular 6"X9" trade paperback trim size, you'll need an image that is 1838 pixels wide and 2775 pixels high (the extra pixels are there for the trim to final size). You can calculate pixel sizes for other trim sizes, easily Since you'll be using a Bleed image for the cover, make sure there is ample space around the featured content on the cover to allow for the trimming. If your Kindle version cover isn't large enough, you can try resizing it, but print out the final image in a size to match your trim size and check for print quality. I went ahead and doubled the size of the Kindle cover image file, and it looked just fine. If you know you'll be publishing both the Kindle and paperback versions, design your front cover to match the pixel size for the paperback from the beginning.
5. After uploading the cover file, choose a cover template that puts that cover image on the right side of the cover. There are a couple of those available. The KDP Cover Creator will pick up the background color of your image and apply it to the spine and back cover. It will also automatically put the title and author on the spine, and the ISBN bar code on the back cover. You will add text for a book description, an author image, if you want, and an author bio. Proofread those carefully, and use the Cover Creator's AutoFit font size to simplify formatting. If you have the cover graphic file ready, creating a cover this way can be done in less than 10 minutes, and it looks great. Creating a print-ready pdf file is something you should hire a pro to do, so you'll probably want to go with the Cover Creator.
6. With the book's content uploaded and a cover design created, you can simply click the Preview Button. The KDP software will check everything, and it can take some time. When it's done, you'll see a preview of the cover, and will be able to preview the inside pages as well. WARNING: If you see errors called out on the left column of this preview screen, don't ignore them. They're critical. You'll have to correct them in the Word Document and upload it again after making the corrections. The preview screen will show you the page numbers where the errors are. Click the page number to jump to that page, where you can see the problem as it will print out. Switch to the Word document, go to the problem page and correct the problem, then save. Do this for every page that has an error. Hint: click the Paragraph Mark in Word's Home editing ribbon so you can see spaces, tabs, and other hidden formatting characters. this will let you spot the problem and correct it. Save after each correction.
7. Once you've fixed any problems shown as errors in the KDP app, upload the Word document again and click the Preview button again once the upload is completed. Keep repeating this process until no more errors show up at the left of the preview. Once you get to that point, scan all pages visually to make sure things look OK. Then, you can click Accept to complete the process. Be prepared to repeat this a few times. For my wife's book, this took about six passes before I had eliminated all errors.
8. Once you've accepted the completed formatting process, you can go on to select a price to charge for the book and complete other parts of the publishing process. When everything is finished, KDP will tell you that it might take up to 72 hours for your book to show up on Amazon. My wife's book was up and available for purchase the next morning.
9. TAKE YOUR TIME! Use the KDP Help screens! Double-check everything! Plan on spending two or three hours from start to finish. It could take longer if you're not a Word expert. In the end, though, you'll get through it all.
10. It's all FREE! What a deal!
NOT AN AD: Here's the final result from my work yesterday on my wife's book:
https://www.amazon.com/dp/1983047384/ref=sr_1_2?ie=UTF8&qid=1527954721&sr=8-2&keywords=dopamine+diary
= new reply since forum marked as read
And yes, I'm well aware of the on-screen convention of the space between paragraphs. I obviously use that myself. I rarely read on-line, other than things like DU, which is not quite like reading a book.
I'm likewise a voracious reader. I cannot understand or relate well to people who never read.
I do know that it's possible to format on-line so the printed product will look like a very conventional book, but I have no knowledge of how to do that myself.
Anyway, I hope your wife's book is wildly successful. 
I think the Microsoft Word environment frequently makes projects like this more complicated than they need to be.
Creating a plain text paperback ought to be a one-click function. Maybe it can approach that if you learn the "Dos and Don'ts" of Amazon's KDP and start with one of the KDP Microsoft Word templates, taking great care not to change anything in the document but the text.
https://kdp.amazon.com/en_US/help/topic/G201834230
If I ever decide to publish my bad novels, most of them explorations of my own madness, they're all written in plain text, the earliest using vi, and the latest, Markdown. Pandoc can effortlessly covert those into epubs or MS Word documents.
The "word processor" I use on my chromebook is mado.
Keep it Simple Stupid keeps me out of a lot of trouble. Write plain text first, make the document pretty last. Always save your final document in a plain text format.
For a few years I did most of my writing on an Atari 800 using Paperclip. Those files were easy to convert to html with a simple batch file when I moved on to PC compatible machines. I wrote a little Turbo Pascal program that would extract and convert files directly from Atari disks.
For a time I was writing html, <i> </i> for italics etc., but grew to hate pointy brackets and slashes. Anything XML is fugly.
