packer.settings file & execution

Hello, I am new to crossref environment and programming, so I would like to know how to run the pack-to-single-jsonl function. I have installed the package and requirements, but it seems to be a packer.settings file missing. What should this file be/contain?

Also, do you have an estimate of the size of the jsonl created using the lastest release (from april 24; about 200Gb) data archive?

Many thanks, and sorry for the (probably unconventional) issue.