Help with Pono?

Can anyone help me get my Pono to load music onto the SD card? I've written to the Pono Help folks 4 times now and the problem still isn't solved (they seem pretty clueless). Maybe I just don't understand how to do this. The tutorial video seems to imply that when loading music, I can drag files to the SD card, but the SD card isn't showing up near the place on the lower left of the screen where I drag and drop files to the Pono itself, which has worked find.

FWIW, I'm pretty impressed with this thing otherwise. Sounds a lot better than my old iPod or newer iPhone. I'm really surprise so many people haven been negative about this thing. Although I definitely think their communication with customers and instructions for how to get the most out of it need to be improved.