play multiple concurrent streams

Hi All,

I'm running the latest release ( built from source "midish snapshot, aug 10
2019" ) under Debian 9. So far so good. I can record a track from my
Keystep and play it back to my IK Uno synth.

I'm afraid I need some hand holding for the next step, though.   I'd like
to use the keystep to play several different parts one after another,
recording each in midish.  Once I have them, I'd like to play them back to
different devices ( each on it's own midi channel ) at the same time.

Is this something midish can do? How do I launch multiple songs at the same
time? A step by step example would be greatly appreciated.

Thanks,
roue