"Horno" is a free Adobe FrameMaker Paperback template.
It is pretty simple stuff. It adheres to common paperback dimensions.
It comes with a settings file for creating pdf's and another settings file for creating epubs.
I have made a master page mapping on the reference pages which will allow the user to map master pages to paragraph tags.
I have made made a small video instruction to the template on my Youtube channel here: https://www.youtube.com/watch?v=NCkn4vMsK9o