Dilaco, I have taken your comments on board.

I think that you have to balance what is being offered here to what you had been considering in procuring an external package or product. If you had, you would have no instruction on how to integrate it into a Xara design.

I would have placed the Audio Player construction as Easy.
Bulk MP3 Uploading as Medium.

There comes a level of awareness that no one would reasonably be expected descend beyond.
I do no explain Placeholder or other terms that are part of Xara.
Knowing how to add a Link to a thing in Xara is basic 101.
I do not expand on MP3, JS, CSS unless there is a direct and important association.
If it is a Windows action, like finding a file, then I am not the person you should be asking for advice.
If it is code then you can search on the internet for HTML5 Audio as I offered earlier to get an explanation for what it encompasses.
Did you look at https://www.w3schools.com/html/html5_audio.asp, then https://www.w3schools.com/tags/ref_av_dom.asp to understand the richness of just the <audio> Tag?
Did you look at @Initiostar's examples?
If you haven't then why should I be explaining 'src' or other terms?

I had believed you have been following the Thread, as all of it is reflected in the PDF.

The PDF was there for you to work with the material I already provided. The linked design file you already have.
I really think you ought to work from that first. I have added a suggested approach at the bottom of the revised PDF.

I have abridged everything needed into the the Approach Summary, near the top of the revised PDF. This would be for experience Xara users but is still the pathway for what a novice has to address.

The flow of the PDF is correct.
If you jump to a section then it is incumbent on you to come back and continue.

Here is the revised and corrected PDF: MP3 Audio Jukebox.pdf.

Thank you for pointing out the internal links are not working.
I have made them explicitly indicate the heading they should be going to.

Acorn