HEELP!!!How do I Find the Original Instrument In the Mixer

Try with the broken arrow at the top , it makes one step before each time you click

I assume you mean that you changed the Sound part of the instrument's mixer setting from the default (e.g. "Orchestral Kit") to something else (e.g. "Marching Tenor"). To find the default setting just temporarily add another of the same instrument and see what its settings are in the Mixer.

Or go to staff properties and change the instrument to snare drum and it should revert back to the default in the mixer unless it came from a template, then all bets are off.

Lol, I go to edit menu, instruments, add the same instrument that you're trying to find the original mixer instrument for or duplicate that instrument, see the original instrument they use for the botton channel of the mixer, then go back and undo adding the last instrument or duplicate to be back where you started...it's a putzy way but that's my node way around it if you have trouble with other's advice. Lol