Browsers can't autoplay video and audio without the user's permission, and that permission is given via input events, mainly the click event. When you press the 'continue' button, you send a click event to the browser, which grants the script permission to play audio.

There is likely an event listener on the 'continue' button that when pressed simply runs the audio script, which is allowed under autoplay rules (user interacted with the page). Not sure if that's actually the case since I'm currently on a phone and my internet connection is pure dogwater so I can't even get past the continue button.