AFAIK this is not a supported method even though it has been requested over the years (lots of years)
Calibre can ADD from Folders and Sub Folders. But it can't derive metadata from the file path.
2 plugins come to mind that may help
INSTALL and configure the next BEFORE importing
GetFileName
https://www.mobileread.com/forums/sh...d.php?t=278559
Then use the Metadata editor Bulk Mode to parse SELECTED ROWS, and fill in columns.
(
Backup between BULK use. Bulk mode has no undo if you get it wrong )
Another is use the OS DIR (recursive to get full path) to pipe the directory into a text file, then use
Import List plugin
Again, these are advanced techniques and need CARE or you get a mess