I must warn you, I haven’t fully figured it out. But the easiest way is to use copies of audio samples and create your own UserDataAudio object, which you can copy multiple times.
However, this is only theoretical, since I don’t have time to figure out how to create sound programmatically.
Thanks to the extensive forum, I found an example.
It remains to figure out how to get the data from the audio sample buffer from your uploaded file.