The transfer is done online not directly into the unit.
Find the "Vault2" in you computer files , click it to open 2 files: Music and Rip.
Drag and drop the music from your computer or computer-attached HD into the Music file. Blue light on Vault will flash red as music is being copied.
When copying is complete open control pgm and tap bars on upper left. Go to Settings- Music library- Reindex music collection.
In a short while your music will be organized and ready to play