How to access extra installed disk from Cubes OS?

I received my NitroPC and I am experimenting with Cubes OS.
I can see volumes varlibcubes > data and vm-pool > data & metadata which seem to be in total 4 TB.
But there is supposed to be another 2 TB SATA disk installed in the NitroPC.

How can I ‘mount’ that disk and make it available to the different cubes in Cubes OS ?