I used Google Docs (now called Drive) to type my material, and insert diagrams and images. I did use titles, headings, subtitles to give the documenty some structure. The great thing about Google Docs is that it's free, accessible from almost anywhere with no need to install software, ... very convenient and efficient. Your content in Google Docs can be exported in a range of useful formats, including Microsoft Office, ODF, PDF, and HTML.
The steps for making a Kindle ebook is simple:
- Export your doument as HTML. This will give you a zippled folder with the content and any images that you used.
- Import the main HTML document into Sigil. Use Sigil to add a cover, book metadata such as title and author, and contents. You might like to split up a long document into separate HTML sections. This is also your opportnity to clean up the content, remove additional spaces, blank lines, centre things that weren't.
- Export an epub from Sigil. This is an open file format for ebooks, and quite well supported by many readers but not perfectly, as I said above.
- Amazon doesn't like epubs so they convert it to their own format when you upload it to their site.
You might want to use preview tools to check your epub file works and get an indication of what it might look like on real physical readers.
Just this week I fixed an annoying problem which seemed to only affect Android Kindle readers which seemed to force very wide margins, meaning the content was squished into a very thin column. The usual internet search led to messing about CSS styles to override the margin, border and padding settings. It didn't work. The answer was actually to go back to the Google Docs document and use the page setup menu to zero the page margins...voila! That worked!
Hope this helps someone else.