Help setting up pocket beagle?

I downloaded the latest image on the beagleboard page, Debian 9.3 2018-01-28 4GB SD LXQT

I burned it onto my microSD card and put it in the pocket beagle, then plugged the pocket beagle into a USB port on my computer. The power LED is steadily on, and the user LEDs are flashing normally as described for the system defaults. So at first all seemed well, but the PocketBeagle never pops up as a USB storage device, nor as a network adapter. Not sure what I’m doing wrong here, or what I’ve missed.