Help with how the sound/music works?

I'm changing the music for my Roman games. I've pretty much figured it out, but I still have a couple technical questions.

The .txt file, descr_sounds_music, has the following lines near the top.

music_timeout 60
music_retrigger 20

1)When do these get triggered, and what specifically are they?
2)What file actually triggers the music? For example, if I'm in a battle, what file/script is being called upon to check the "states" of the music? Or can I not access it?
3)What does placing "looped" after the keyword "event" do, i.e. event looped?
4)During battles, I'd like the music I'm adding to play, without being interrupted by an event, until that song finishes. Right now my songs get cut off pretty quickly. Is there a way to mod it so that, during battles, new music events wont be triggered until my song finishes?
5)I'm noticing that usually only certain songs will play during the campaign. When does one of the other songs get triggered, only during summer? Is it random or does it go in order? Is there a way to make the following files loop, meaning all 6 songs play, then they start to play again, with maybe a 20 sec delay between songs? Look at the following code as an example. I'm having trouble figuring out how it actually works and what triggers it.

state MUSIC_STRATMAP_SUMMER
event delay 5 volume -20
folder data/sounds/music
Rom_Camp1.mp3
Rom_Camp2.mp3
Rom_Camp3.mp3
Rom_Camp4.mp3
Rom_Camp5.mp3
EB_Roman_Theme.mp3
end


Thanks,
Apple