If so, go to options --> media card. Ensure Mass Storage Mode is 'on'
Now plug your device to the PC. Now open your music folder and then open up My Computer --> locate the drive corresponding to your BB and then drag and drop.
U have to have SD card first. When U plugs Ur BB to ur computer, it will show * mass storage mode* make sure U click on YES. than Just Drag ur music to ur SD card.