Connect Behringer Model D to Cubase?

Hey guys!
Its my first time using an external synth and I have no idea how to make it work ! I really need your help here …

Some details :
I am currently using a Fireface 400 soundcard
Cubase 9
and I want to activate Behringer Model D to act like a VST.

I plugged a guitar cable from the Model D “High” output to my RME Instrument input (number 3), a midi cable from my Model D to my midi controller and a midi cable from the Model D to my mac.

I opened a midi channel on Cubase, chose on output “MODEL D” (it appeared automatically) and on channel I selected “All”.
I turned on the model d, turned on all the volume knobs and so…
Is there anything I am missing?

You need the audio signal, from the D .
Create a audio track (input 3) and enable monitoring .