This dialog is accessed through menu File / Print / Project / Change.
It allows you to select which portion of the project is going to be printed.
For help on the books selection part, see Selecting books.
To print only a portion of a certain book, double click on the portion at the right of that book. Then you can choose to print from a chapter.verse till another chapter.verse.
To exclude a book from printing, just unselect it.
Everything can be done with either the mouse or with keyboard shortcuts.