Is it possible to save files from my Mac HD to an External Hard Drive? (i.e. I have a folder on my Desktop called "Sting" and I want to move these files to a folder inside the "Music>Rock>Sting" folder on my named external hard drive). I guess I should be more specific. I want Mp3Tag to move the files to the folder on the external hard drive and if that folder on the external hard drive doesn't exist, can Mp3Tag create that folder on the external drive?
Yes, that's possible! Can you have a look at Rename Files and Import Tags from Files and see if it answers your question? Please don't hesitate to ask if something is unclear.
And regarding the formatstring: let's assume your external drive is named
Target. A valid format string for renaming via Convert → Tag - Filename would then begin with