Question about Chorus in Ancient Greek theatre.

So I've been recently reading Antigone and understanding the Chorus is being a little nuissance for me, I'm not exactly sure of how they function and what their role is, are they like a narrator? Something else entirely, I feel like they can be a bit 4th wall breaking if that makes sense.

Idk, I guess I'd like to know more about choruses and what their role within the play is.

Thanks!