[Plugin: EsAudioPlayer] No idea how this works

It’s a shortcode. For example:

[esplayer url="https://example.com/wp-content/uploads/sample.mp3" width="200" height="25"]

You can find more info about using it here:

tempspace.net/plugins/?page_id=131

Definitely one of the best HTML5 audio players for WordPress I’ve seen! Simple and easily customizable.

Thank you for your response, George! Very kind of you. However, I got so frustrated that I went on a search and did actually find a much, much better and much better supported, though not free, plugin called WordPress Media https://codecanyon.net/item/wordpress-media/162186

Thanks, though!