
The very first thing I want to say is this: Do not not NOT do business with anybody who wants to charge you for publishing your book. That means stay away from any of the Author Solutions companies (AuthorHouse, iUniverse, xLibris -- there's a whole list of them) and America Star Books (which used to be PublishAmerica). Those people will charge you thousands of dollars, promise you the moon, and not deliver.
First, I format my manuscript in Word according to the Smashwords Style Guide. It's a free download and you can get it in any format, even pdf. I just follow the directions in the style guide and save the file as the Smashwords version of my book.
Next, I run a find/replace and swap out "Smashwords" for "Kindle". I also swap out any links to my books and author page on Smashwords for links to my books at Amazon and my Author Central page there. Then I save the file as the Kindle version of my book.
Only then do I start farting around with formatting the original file for print. Then I save that one as the CreateSpace version.
You need a couple of other things before you're ready to publish your book. One is the cover, and you have to make sure that you can read the title and author name when you shrink it down to thumbnail size. So think about that when you're designing the cover.

Once I've got my file formatted, I go to Smashwords and upload the Smashwords version of my book. It will walk you through the process, and your book will be live at the Smashwords store as soon as the upload process is complete. With Smashwords, though, there are a couple of extra steps to get your book into the Premium Catalog. You definitely want to make sure you get that done, because that's what gets your book to iTunes, Barnes & Noble, Kobo, and all the rest.
When I'm done uploading to Smashwords, I go to Kindle Direct Publishing and upload the Kindle version. It takes KDP about 12 hours to approve your file, but then it's available immediately at all the Amazon storefronts around the world.
I use CreateSpace for my print books for a couple of reasons. One is that I found their process to be easier to understand than Lulu's. The other is that CreateSpace feeds automatically to Amazon, whereas it takes longer to get your paper books up at Amazon if you use Lulu. Anyway, there's a whole process that CreateSpace will walk you through. Don't forget (because I always do

So that's a very basic (and not at all detailed

