Understanding 'enter viewport' animation; it doesn't start automatically?

I’m trying to understand the animation that starts on ‘enter viewport’. I created an animation to display a hero section on ‘enter viewport’.

When I view the site it has an empty screen. It looks the animation only starts when you scroll?

What am I missing here? I want the animation to start immediately, not ‘on scroll’.

This is especially not a good user practice on mobile; people don’t scroll on mobile, except when they have to.