Cubase 11 and Expert Sleepers ES-9

I’ve recently added an Expert Sleepers ES-9 to my modular, to get sound out from there and into Cubase 11 Pro. All looks ok, Windows (version 10, 21H1) sees the ES-9 happily. I can add audio in’s from the various ES-9 channels over USB and I can see audio coming in. However, I cannot see how to get audio out. I know the device is working as a competitors production suite works fine - but I wish to use Cubase as my primary music creation tool. Has anyone else come across this and if so, what is the undotted i that I am missing?