Exactly that: the location (path) to the files
--probably easiest to dump the songs to a folder on your /home or music, which I think is one of the default /home folder names provided: you can always make your own
the path/device has to be working (readable) in order to get the data: file(s)
Or use a usb device and collect them there, and decide where you want them, the other choice would be the default /home directory (folder) that rhythmbox uses (should be a hidden, dot (.rythm???) folder name, and your other songs will be there
--a quick find is to use the file manager you have and search for a song that works: that will
I can't find any user guide, that covers much, but the help within the program should be enough, and if you need some file that is not being included, check your package manager to see any additions that exist for rhythmbox..