https://codepen.io/parpar78/pen/zYoyEmO
Hey there,
The animation has already finished before you scroll, you can see the animation if you add a duration like i did here.
But you probably want to look into something like adding a scrolltrigger (https://greensock.com/docs/v3/Plugins/ScrollTrigger) to start the animation at the right time.
Take a look at what they did with the other animation in the codepen and check out the docs for more info.
Kind Regards,
Patrick Rijkee