The Import command on the B2 allows you to load music from a USB drive plugged into the USB port. The music files must be organized in a top level folder named music, which contains folders each named for an Artist, each of which contains folders named for an Album, each of which contains the song files.
music\Artist\Album\tracks
The song files must be of one of these formats: WAV, FLAC, MP3 or AAC.
The Brennan website has a lot of information that you might find useful. www dot brennan dot co dot uk (use a '.' insead of " dot ", of course).