Cubase AI elements 12 +input/ output issues

I have a Yamaha DGX670 + Yamaha THR30i. How do I get Cubase to use these properly.

It seems to see the keyboard OK, and appears to record. I, however can get no sound out of it. My THR isn’t anywhere to be seen - it can’t even be found in the input/output dialogues.

Any suggestions anyone, please?

Are you trying to record MIDI or audio? When you say you can get “no sound out of it”, under what circumstances? It doesn’t produce any sound at all from its internal speakers, headphone output or line output?

Are you on Mac or Windows?
How do you intend using this? Do you have an ASIO audio interface already?