How to create stacking layers parallax on scroll?

Heya, Apologies if this is a simple or obvious answer I’m just starting on webflow.

I am trying to replicate the sliding reveal on the opal about page. link:About — Opal

Ignoring the simple fade effect, I’ve been using a parallax effect animation to shift the bottom layer of each scroll. However, it often looks a little jumpy and doesn’t give the effect of the bottom layer being revealed. Am I going about it the right way with a parallax or does anyone have any advice?