By the way, you can use these codes both in the new level editor under the Edit triggers as text button, or in the old level editor of course.
To make the process faster, I took screenshots from the ingame files.
Consider it as DefineSound(X: Y)
Y is what you take to put into the trigger.
Spoiler: Show More
The ones that are not mentioned in the PlaySound action, that might be interesting, are:
gameplay_song - The generic battle gameplay song.
main_song - The main menu song.
am_base - Base ambient sound.
am_wind - Wind ambient sound.
For the songs to play, you need to have the music volume option on a value which you can listen to.
All the sound files for download, in the form of a .zip file:
https://www.dropbox.com/s/0sxvqzzgbkwel ... s.zip?dl=0