Dealing with MBox

I exported the contents of an email discussion group at groups.io.
They sent 788 emails in an MBox format. I researched options and downloaded thunderbird to work with them.
I open Fast MBox editor and followed instructions. If I instructed it to open as a MS Word doc, it opened one email perfectly. If I instructed it to open as text, it opened everything in source code.
I would like to do the following:

  • Open an entire MBox to create a single document in MS Word (Mac OS)
  • Open a subset of MBox (all the emails from a single person or on a single topic in one MS Word document.