Creating photobooks with Elements is my favorite way to make my family photos and events available for future generations... For instance, I create books for events and year books.
Let's be clear: Greg is right that there is no longer a way in Elements to deal directly with a supplier to transfer your creation as a single multipage pdf file for exchange with your provider.
You can create a book that you print yourself on your home printer.
On the other hand, you can probably find locally a dozen of suppliers who offer ways to create your book online, with a free dedicated tool to work on downloaded jpegs or by sending multipage pdf files.
I consider that PSE is one of the best tool to create your custom pages for books or scrapbooking.
All mentioned suppliers have ways of downloading your pages in jpeg format.
So, creating a book means creating freely each page in Elements or using the collage tool; then uploading the corresponding jpegs.
The requirements of online printers define the number of pages (often by multiple of 8), the dimensions and resolution needed as well as the safety margin.
I prefer to upload a batch of one hundred jpegs rather that to create a multipage pdf from an external tool (dedicated like Acrobat or Indesign, or a virtual pdf printer like Microsoft Print to pdf).