first read this topic about filenames and such in the library
https://www.mobileread.com/forums/sho...d.php?t=119175
Second, Calibre by default uses the metadata I think to retrieve title and author.
If you already have files outside of the library named according to your preferences then go into Calibre's preferences, on the third row click the red book, "Adding books", this opens a dialog where in the top-left is an option to read title and author from filename rather than from the book's metadata.
However, be prepared that when the book is added to your library, the physical filename and folders WILL change to shortened versions due to platform compatibility requirements (some OS platforms still put limits on handling long paths/filenames and since Calibre is platform independent, its file-handling code has to work on all of these filesystems)
After the books have been added, you might want to consider updating the internal metadata with your titles