I'm having trouble using the music editor. The instruction manual doesn't list an input for interacting with the editor. And, nothing I press has any kind of feedback. So, I'm not sure how to use it?
Ah, apologies. I assume you mean this tab:
If so: the way this works is you can arrange existing SFX into patterns.
Use the little round buttons (like the one under the cursor in the screenshot) to turn a channel on or off for the current pattern (pattern zero, in this screenshot).
Then, you can click the left and right arrows for that channel to select an SFX to play on it.
As for the three toggles at the top: Loop start and loop stop allow you to create a a sequence of patterns. When a "loop stop" pattern finishes playing, the audio system will search backward to the nearest pattern with "loop start", and resume play there. If no such pattern is found, it will play from pattern zero. "Stop at end" tells the audio system not to play the next pattern when this one finishes.
Let me know if this clears things up, or if I've missed anything! :)