Oh, boy. Are you ready for a bit of work?
Here goes.
Actually, I recommend reading the end part first, the bit about knowing what you need to do to deposit a copy in your country.
Anyway, back to the spiel ...
Don't start until you have an Amazon sign-in. When you go to create a kdp account, it will be the same user id and password. Setting up first saves frustration.
Start with Amazon first, and over the next few months learn the other sites (Smashwords, which will become D2D (Draft2Digital) soon, Google, iBook, Kobo, etc. There may be others.). That gives you time to do a 90 day period on KDP Select (free to Kindle subscribers, and gives you some small marketing bits) but make sure the box for ongoing is NOT ticked.
Amazon is the easiest, and if you follow the instructions carefully and use the save function for each page but don't press the final page save and continue, you can go back to fix or check things. Yes, know how many pages there are before you start the upload.
You'll need a
cover. There are plenty of places to make a cover to fit the size req's. Some of the other sites will have different size/pixel req's. Know what they want before you start (Google is your friend to find the req's for each one - use the best pixel ratio to show off the cover and title).
Cover Image Guidelines //
What criteria does my eBook's cover image need to meet?
Canva is useful for setting up and prepping a book cover, and there's a free version. Play with it before you use your cover, and always keep a couple of backups of things you like/want to work with.
Fonts - there are fonts that are free to use, but many are not and require payment/permissions. Check it out before you start. This applies to covers and internals.
Internals - eBooks are not the same layout as paperbacks. eBooks should be simple or you'll run up the memory and 'zon could start charging you extra for transmission. Keeping it simple saves you the pain of wondering why you have to pay for people to buy your book.
What does simple mean?
The
title is in a Title font, the copyright pages are in a simple copyright font (usually smaller, often centred, and on the same page as the ISBN and publishing details, including your copyright symbol, your name, and the year of publication, ie Copyright © Rich Dude, 2022). Copyright pages and publisher info can go at the front or the back (back would also include 'About the Author' page with other publications or contact details, website, etc.).
Now for the bigger issues. The
text of the story.
Chapter headings are in a
style, always a style, or the reader won't be able to 'see' the chapters/headings. I recommend a Heading2 style and use it for all chapter headings (if you use words in chapter headings, you can also easily do a TOC at the beginning or end, but for eBooks, if there are no words, I recommend not doing a TOC that just says Chapter 1, Chapter 2 ...).
All chapter headings need to have a '
page break before' as part of the style.
The
first paragraph of each scene/chapter is not indented (use a non-indent style to ensure consistency), and is not justified. All
following paragraphs are indented using a style (normal, perhaps with an indent of .25" or 1.5cm) and not justified.
If you use tabs, double spaces, double returns, or justified text, the output will be unexpected, to say the least.
For
a new scene that isn't a new chapter, use a blank line, a
colophon dinkus (something like 3 asterisks or a hash sign are the simplest as some
colophon dinkus are also copyrighted and require permissions/payments).
That's the simple version. I'm not going into the req's for a paperback. I recommend putting the eBook up first, then learning about the req's for formatting a pb - it's not the same and it takes time to learn it. When you pay someone to do it for you, it needs you to check every detail, not just text/placement. Know what verso means or why it's important? Why page numbers go where they do? Why not to use whitepaper? Why single-space works best? Which font makes for easiest reading? Should a chapter start on a verso or recto page? Etc.
However, I'd also recommend making sure the story itself is in the best shape it can be. Don't risk using an author name you love and then find you're being rubbished for an unfinished or unprofessional publication (someone may speak from experience).
Also, learn the req's for the country of publication. Do you need to lodge a copy with something like a national library? Do they have req's? Know these before publishing.
That's enough to start with.