Don't know how to use Audio-inator? No problem I got you covered!

Once you've downloaded the script you can just toss it into your project via drag and drop into the Godot editor file system.
Next you can take that script and toss it onto an AudioPlayer, if you're using it on a positional audio node such as AudioPlayer2D/3D you'll just need to change the script node type; but it should run fine beyond that.

This piggybacks on the existing AudioPlayer node's built in functions giving you some extra flexibility. So you can use the fade_out() function to drop the volume to silence.
You can also use the fade_in() function to bring that audio volume back up!
Trying to switch tracks? Use the switch_audio(_new_stream) function and feed it a new audio stream file to play and it'll handle the rest.

Any further questions feel free to ask and I'll update this!