I got an 1824c recently, and I'm totally new to recording, mixing, DAWs and all of it. Can someone explain the primary purpose of the "main" output? I see a giant knob to control its level, and presumably the dedicated mute button applies to it as well, but none of that has any effect on what I'm actually hearing through the headphones. What is the philosophy behind "main" and it being different from what goes to the headphones? What do people normally hook up to the main outputs on the back?

As background, I'm using my setup to record drums.