How Do I..?

Q: how do I attach an audio file to play when a trigger is actioned by a player/DM?

I tried following the YouTubes I could find, and even the tutorial for triggers. I am still at a loss as to how to set this up properly to work.

effect I am seeking: when a false door gets opened by a player, elsewhere in the dungeon, a gate slams down shut.

this appears like it should be straight forward and fairly easy to set up.

Things I have managed…:

I found the difference between audio files, and object audio files…
I have found the settings for the trigger, and put triggers into place where I want them. (I can change the color, and dimensions of the trigger)
found I can attach an audio file to a map, not sure if map can be linked to audio file…
found I can upload an audio file to the VTT
I am seeking an exhaustive list of tutorials on the subject to help review, and see if I am missing that one little detail… please post lists of relevant tutes, please.