How to use trimming pdf or crop box and trim box

Thank you for using ComicGlass.

A setup of trimming can be set up with PDF editing software, such as Acrobat.

I don't get it: what is this option for?
Your documentation is really poor, and you really should put an online manual of some sort!!

I am sorry that documents run short.

The trimming of PDF is the specification of a PDF format.
It is the function to set up the unnecessary portion of the scanned file.