"Due to the new autoplay policies in some browsers, audio and video on the first slide of a course might not work. To fix this problem, Articulate added a play button to Storyline and Studio courses that have audio or video introductions. By clicking the play button, learners give their browsers permission to play the media..."
Storyline and Studio: Media Doesn't Autoplay When Slides Advance Automatically
And:
"Google no longer allows videos with audio to autoplay in Chrome 66+. As a result, a video on the first slide of a Storyline or Studio course might not work. Here's how to update your courses so learners have the best experience in Chrome..."
Storyline and Studio: Videos Don't Autoplay in Google Chrome 66 and Later