You need to select advanced options and then click the layers button.
If you can't see the layers button use the top menu:
Window >> Layers
It should be possible to selet the layer with the cover and edit it.
Where do you get the photo book printed? I live in Toronto and just learning the program. I'm trying decide what program is better. I'm thinking i may go back to creative memories old program
It’s difficult to answer your question because Adobe has selected different partners in different regions. e.g. Photoworld or Shutterfly. I’m based in England so have no idea of the local services in Canada. So you need to do your own local research. In the Organizer you can click on the share button and if you choose photo prints it will probably be the same partner for books. Some users will be happy to print their own pages at home but I prefer professional book binding. If you are still unsure there are sites like Blurb which I have used successfully in the past. They even have web based templates for designing your books; you simply drag and drop your photos and text and order on-line and they deliver through the mail. You could even design pages in PSE and then use Blurb.