Hi Jonhenry,
Please ensure that the sound is turned on see screenshot: 

https://mega.nz/file/SwsnGC6K#59WZB4qFDrzhQRhN0KTGaO_wjL0yFTa44H6H5ao11XA

(If you're using a mobile device, you'll find the sound settings in the bottom left corner.)

If the sound is turned on but you still don't hear anything clear your browser's cache or try using a different browser.

Kind regards,
John