Above is a video explaining the basics of ebook publishing, formatting and conversion. The video below will show you how to convert from Word (.docx) to epub and mobi formats with my free ebook conversion tool.
And this video will teach you how to edit your epub file with Sigil
That's the simplest process, which I recommend for beginners. But I'll start adding individual videos here for each separate method of making an ebook (From InDesign, through Scrivener or Jutoh, etc); I plan to have about 25 of them.