So I'm relatively new to Music Creator and Zeta.

In short, I have the Zeta plugin working fine on a singular instrument track, but I want to use one soft synth on multiple tracks. I tried instead when adding a synth, checking the bow that said "All Synth Outputs: stereo" or something like that. Unfortunately that did not seem to help. My controller would not make sounds when that track was the only track.

So how do I do it?

Thanks.

Welcome tigerjp27,
 
I don't use Zeta,  however, many synths, although having multiple outputs only have the ability to handle one input source track at a time.  Zeta appears to be in that group.
 
To get Zeta to work with several tracks, you simply have to use a new instance of Zeta for each track. That will work.  With Music Creator, you can have up to 8 instances of Zeta or 8 combinations of other synths at one time.
 
Most synths are of this singular input nature. 
 
TTS, which is also in your MC6 DAW,  is different...... it's  a synth that WILL  allow you to use up to 16 midi tracks, each assigned to a different channel in TTS, feeding just one instance of the synth TTS.
 
On my web site, under Recording & Music, MC, there are some things that you may find helpful on how to use TTS with several tracks of midi source. Scroll down to Advanced TTS set up.
 
Hope that helps.