How to find external SSD connected to USB?

Finally up and running with Nucleus Core running 1.7 to a GSi75, thanks to an updated USB card from Audio Research. Next step is to connect an external drive with ripped music via USB.

The SSD disc has been formatted in exFAT and CD’s ripped via dcPowerAmp to FLAC, however when connected to the Nucleus Core the SSD doesn’t appear in the Roon application on my iPad. How do I access this material?