How to turn off internal piano sound

Hooksong

I simply want to silence the internal piano sound, when I have a midi keyboard connected to the app. I am scoring piano music in real time, using a digital piano and midi into the app. I need to hear the metrononome as I play, BUT NOT the annoying piano sound coming from the app. How do I silence it?

Hooksong

I figured it out. It's under the metronome. Not intuitive at all. But at least I can do it.