Keep "Saving Progress" as you go, to save what you have. You can log out and log in a week later to work on it some more.
When you are finally ready for CreateSpace to take a look at it, you want to click the "Submit for Review" in the lower right.
This process normally takes 1-2 days. Be patient. They'll get to it soon.
Usually they say it's good to go. You can then order a proof copy or just review an online version of the proof. Either way you can keep reloading and rechecking as much as you want. You can order a proof copy, revise it, order another proof copy, revise it, and so on, for months on end. There's no rush.
You decide when you are finally satisfied with it and ready to put it live.
CreateSpace Step by Step - main page
CreateSpace Self Publishing
Loading Up the CreateSpace Book
Making a CreateSpace Cover
Channels and Pricing on CreateSpace
Review Process on CreateSpace
Timing of CreateSpace Process
Problems and Issues with CreateSpace
Lisa Shea's Editing Services
Lisa Shea Free Ebooks
Lisa Shea Full Library of Published Books
Getting Your Book Published
Writing Tips and Online Books
Lisa Shea Medieval Romance Novels
Online Literary Magazines
Lisa Shea's Homepage