How to initiate animation at specific scroll position

How can I make Figma start an animation (button appears) at a certain scrolling position on a website (I am not talking about parallax)?

Hey Kevin! Thanks for reaching out to the community.
At the moment, this is not possible. Others in the community have requested something similar, feel free to vote up and share your feedback here: https://forum.figma.com/t/on-scroll-for-prototyping/482
As a workaround, you could set it to trigger on hover of that section (https://help.figma.com/hc/en-us/articles/360040522373-Prototype-animations#Instant). Hope this helps!