What’s a library?
A library is basically just a folder or collection of folders you want to apply flows or rules to.
Should I add one library per TV Show?
I do one for Movies, one for Shows, one for Anime.
Transcode options
There are example flows, I would use one of those and just modify the options to suit your purpose if you are not a power user.
There are videos for setting it up. https://youtu.be/JFvkJeDQRBQ?t=259
Good luck!