Music (Asset)

Adding music is a bit involved. But there's a tutorial here.

Setting	Type	Default	Explanation
Label	String		A unique identifier for the music asset. Note that you should NOT change this after setting it.
Track Name	String		A name for your track. Helps users find your music.
Author	String		Author of the music.
Download Link	String		URL to a place you can download the track. Optional, but recommended.
Volume	Float	0.5	You can leave at the default 0.5, but if you're making an epic end boss battle you can go a bit higher.
BPM	Int	130	Beats per minute. MUST match your track. Important! Cannot exceed 255.
Simple Fade In	Int	0	If you want the track to just fade in instead of using intro and outro points, you can set the fade in time here in milliseconds.
Simple Fade Out	Int	0	Same as fade in, but on the tail end.
Loop URL	String		URL to your music track. HTTPS is required. Must be an OGG file. Note that after adding the URL, a timeline should be populated in the editor.
In	Int	1	The bar number where it starts playing.
Out	Int	1	The bar number where it should loop around.
Transition Points	Array	Int	Good places to transition to another track when crossfading.
Intro URL	String		Path to the intro audio file.
Intro in	Int	1	When the intro "hits". If you export the loop from the very beginning, then this is the same as the loop In.
Outro URL	String		Path to the outro file.
Outro Out	Int	1	It's what we discussed above. Assuming bar 1 is at the very start of the outro, our outro "hits" on bar 2.

When you've specified all 3 URLs, a widget shows up that shows you markers, and lets you playback your track.