A Simple Question

I’ve divided a piece for a large ensemble into three separate tracks and would like to change the volume in each track individually for, say, the percussion track or the piccolos track. I apologize for the simplicity of this question that has no fundamental connection to the complexity of my music.

IF each instrument is in isolation on it’s own track, then track gain slider controls the volume of that instrument.

https://manual.audacityteam.org/man/audio_tracks.html#panel