Line outputs are unclear and buggy

Nope. Doesn’t work for me at all.

I can’t figure this out either. You’d think that this would be a simple thing, I don’t want my audience to hear the click track, right?

I have a mac. I’ve imported my STEMS I created in Cubase Pro 12. I can see them all, and everything plays fine though the speakers. Great. Now, turn on Metronome so our drummer has a click, right? metronome comes though the main speakers. No matter what I do, the Metronome comes though the main speakers.
I am using UAD Apollo Twin.
So:
Mac - UAD for audio - audio files (STEMS) in Live - how do I get the audio to assign so the audience can not hear the click?

I’m kinda dumb, is there a step-by-step that can show me?