John,
Happy to try and clarify if I can. May I ask you to explain a little further what’s new to you, please?
The concept of a Watched Folder, maybe?
If not, do please explain and we’ll help 
.
If so - then put simply, in Roon a ‘watched folder’ is the only location on your computer, local drive, NAS etc into which you put all music files which you want Roon to work with/import, display and play for you.
It should - basically (there are exceptions: cover art and booklets) - contain contain only your audio files, properly tagged, and ideally well organised. Nothing else. And (at least until you are completely familiar with this aspect of Roon - I’m assuming that this may be the issue for you here, John) stick with just one well-maintained and organised Watched Folder.
When Roon is running, it repeatedly scans your Watched Folder for any music files which you add to it. They then join every other music file therein to become part of your Roon Library.
These pages ought to be a good start:
- https://help.roonlabs.com/portal/en/kb/articles/faq-what-s-a-watched-folder
- Adding a watched folder - #6 by Michael_Burton1
Do say if we can help further …