Split PDF Dialog

This dialog is invoked from the file menu option, 'Split PDF into many PDFs...'.

Filename pattern

This can contain control codes to name the file based on date, time, automatic incrementing numbers and environment varaibles.
The default pattern is '%Y-%m-%d {AUTONUM3}.pdf' which produces files named such as '2018-10-22 001.pdf','2018-10-22 002.pdf' etc.

For details on this, please read
output pattern.

Pages per PDF

Sets how many pages are put into each PDF file. If greater than one, the final PDF may not have the full number of pages.

Auto number start

The starting number for the {AUTONUM} variables in the filename pattern.