Light YouTube embed gallery and Playing one video at a time

I’ve been searching way to embed multiple YouTube videos as gallery.
For performance I’d like to load iframe after user clicks the thumbnail.
For better UX I’d like to stop previous video form playing when user starts a new one.
There is CodePens covering both aspects, but not combined.
Technologies used: HTML + JS.

Thanks!

<a href="https://codepen.io/AugerHybrid/pen/YzadrbP">codepen</a>