system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: what is a director/maestro doing with his hands?

Everybody has his sheet of music, so what is he doing?
gpt
In the most basic sense... you have a group of 40 people that all need to start playing their instruments at the same second. Without the director, they'd basically never know when to start, or the start of the song would ve extremely choppy as people are trying to catch up or figure out when to start. Unless someone yelled out "ok start" and then began playing. The director is that role.

And then, the director keeps tempo and signals coming changes in music. Again, if he wasn't there, you wouldn't know how fast or slow to play. You'd need to just hope that someone is staying on beat and that you can follow them. The director centralizes that. He is leading. Not some random person who should be focused on playing their music.