A few starting questions

[PiDockMedia]

As someone who has been using m4b-tool for a while with a lot of manual setup and post processes, I am considering transitioning to this new tool with the beets container. I believe this will make the process easier, but I have a few questions that I hope you can help me with:

• How does it determine the author, title, and series?
  What pre-work do I need to do to best assure it will get set correctly? Today, I organized them in advance by using Author/Book or Author/Series/01—book1/.mp3...02—Book2/.m4b...03—Book3/*.mp3, etc. Do you think this is necessary or helpful?
• I have a bunch of files already in M4B format but they need tags. Can I stick them in there and will they pass through for tagging with beets?
• I know many completed books in Plex could be more perfectly tagged. I have them all in the folder structure mentioned above. Can I run them through this without them getting modified, and will the beets step make sure they get tagged? Should I just drop them in the untagged folder and let it do its stuff?
• What plugin do you use, if any, once they are in Plex?