My Book Duo - Expanded Storage via Accessory USB Port?

Has anyone tried using multiple My Book Duo’s via the USB accessory port? I’ve read that the two USB 3.0 ports can be used for accessories including storage expansion but I have yet to find any information as to how it’s done. Can a 2nd unit be used and if so what is needed?

yes, those USB ports are for storage expansion

Yeah, I know that. The question is how?

From My Book Duo connect to PC/Mac using Type-C port (this could be Type-C to Type-A cable or Type-C to Type-C cable). From there you can connect any USB devices to the Type-A ports on the MBD.