Hi Jessica,
You would need custom Javascript Code for such an effect which would be out of our scope of support.
Here’s an example of a set of codes that run an effect based on the scroll position: https://codepen.io/tateishi-e/pen/xaEJxw
If you’re not familiar with JS, it would be best to hire a developer to do it for you.
Something that doesn’t need JS which we can help you with are hover effects. For instance: https://share.getcloudapp.com/Z4uA1Jvz
Hope this clarifies!