When you open or create a project in the Motion Book Tool, you will see various options for uploading / previewing your Motion Book.
Here is a screenshot of the project control panel:
You'll notice that there are a set of checkboxes that allow you to specify how you'd like to preview your Motion Book.
If you are logged into the Motion Book tool through deviantART / Sta.sh, you will see an option to upload your Motion Book to Sta.sh.
If you are not logged in through deviantART, and you want to upload your Motion Book to Sta.sh so that you can later publish it as a deviation, please refer to this article.
The first option, "Upload to Madefire Reader (iOS)" allows you to upload your unpublished Motion Book for you to preview. Note that ONLY YOU will be able to see this Motion Book. It will not be visible to anyone else, and you have to log into the Madefire Reader on iOS using the same email and password as you used to log into the Motion Book Tool. For further information on previewing your Motion Books within the Madefire iOS Reader, please refer to this article.
The second option, "Upload to Web" will give you a web link to your Motion Book. Note that this link will require a Flash-enabled browser in order to view the content. The content is private, in that nobody can find it unless you provide a link to it (similar to an "unlisted video" in YouTube. When you check the checkbox and upload the Motion Book, the completion dialog will provide you with a web link. The content will be stored in Madefire's content delivery network.
The third option, "Upload to Sta.sh" will upload your Motion Book into your Sta.sh account. When this is selected, "Upload to Web" is required, so that the Madefire server knows to create a Flash version of your Motion Book. The content will be stored in your Sta.sh account, where you can then decide if/when you want to make it publicly available as a deviation. For more information on uploading your Motion Books to Sta.sh and/or publishing your Motion Books as deviations, please refer to this article.
Note that uploading your Motion Book doesn't make it publicly viewable; it is simply copying your Motion Book for you to be able to preview. Publishing your Motion Book is under your control, and requires a separate step.
In the case of iOS, please refer to this article.