Preferences > Adding Books
Set the Regular expression field to:
Code:
(?P<author>[^_-]+) -?\s*(?P<series>[^_0-9-]*)(?P<series_index>[0-9]*)\s*-\s*(?P<title>[^_].+) ?
That expression should be one of the options in the dropdown...
A book with the filename in the following format should work:
Author - Series Series Number - Title.epub