You can find answers to many of your questions about using Ebook Central ebooks on ProQuest's help pages:
Ebook Central Libguide (a how-to guide on printing, downloading, searching within titles and using the new reader)
Contact ProQuest Ebook Central Support:
Can more than one person access a document at a time?
Most documents can be viewed by any number of people at a time. However, the Vermont Law School Library has purchased some documents that are available for viewing by only one user (or a certain number of users) at a time. If you try to view one of these documents and it is in use, a pop-up message prompts you to put yourself on a waiting list for the document.
I cannot see the document I clicked on – I just see white space.
Ebook Central displays the document as it was originally printed, so blank pages might appear throughout the document. Documents often begin and end with blank pages. Click ahead or back in the document to ensure you are not just on a blank page in the document.
I am off-campus, why can I not access Ebook Central?
If you experience any problems accessing Ebook Central off campus, try these troubleshooting tips: