It seem that browsing the manual is not enough.There is no need to use function.Just song bank button and after usb stops flashing,the songs are in the song memory 41 to49.I'm getting more impressed with this machine as I learn how it works.Of course,the tones and rhythms are casio grade but much improved from earlir (and cheaper) models.At 12.5 pounds, I can carry it easily in the NH and the speakers are quite acceptable.The usb itself appears to only be used when material is wished to be saved and either edited with a program on comp or reloades at a later date.I'm now glad I replaced my old KB with this one.Well done casio