While both the Prime and Core can stream music from Dropbox, using a USB flash drive can be more convenient in certain situations because internet access is not required.
To load your backing tracks via a USB flash drive, please follow the steps below...
1. Load your .WAV or .MP3 backing track file onto a USB flash drive, then connect it to the Prime or Core.
2. Go to Menu > Browse, then select your flash drive from the Storage tab on the left side.
3. Select your audio file, tap IMPORT, then select "As Track".
4. Wait for the track to be imported. Once a green tick appears showing that it has successfully been imported, double tap on the audio file to load it.
5. You will be automatically taken to an audio player screen. Simply press the play button to begin the track. If desired, you can go back and change your rig settings, and the backing track will continue to play in the background.