In a compound sentence, is the comma before or after the conjunction?
The comma goes before.
I am a man. You are a woman.
I am a man, and you are woman.
I am fine but a little bit tired. (note: this is not a compound sentence - hence, no comma.)
I am fine, but I am a little tired. (This is a compound sentence - hence, the comma.)
It is covered here in Grammar Monster.