Adding Audio to Sketchfab models

We have a requirement to add audio to our Sketchfab models embedded on Omeka, and recently Sketchfab stopped holding the audio file within their platform. There is now a workaround which we can make work in JS fiddle but can’t figure out where to upload the CSS and JS

Our site is here
https://omeka.cloud.unimelb.edu.au/against_erasure-manus_island/