Hmm, I followed your instructions step-by-step but still had no luck.
Does the SoundVolumeTrigger have to be set to Global?
Did you unpack any music files from the main game?
Can you preview the music tracks when you double click them in the resource editor?
No to all of those.
Were you able to get the music resource added to the sidebar of the trigger?
Or is the problem that when you enter the trigger it simply doesn't start?
You might want to check your music volume setting in the game from inside the editor too just to verify.
It may not actually work from a teleport, you might have to walk into it.
Far as the pointsoundtriggers go, those are useful for when you need a sound effect but not a visual one.
Example: my mod has a house built on a hill where you can find a secret ladder that leads under ground. But when you climb down the ladder it snaps in half and falls down and you can't get back up. So I added a crashing thud sound effect to a pointsoundtrigger in the instanced area where the ladder down teleports you to. Works pretty well.
The other type of sound trigger I didn't mention before is the Dummy trigger. That's basically the same as the pointsoundtrigger except you use it to place continuous sounds like grinding machinery.