@j36g2 try to inspect the code and figure it out.
You are basically scrolling all layers at once but it just looks like its one after each other.
the approach is the right one. front layer is 100vh, 2nd layer is 200vh, etc., use "z-index" to put them behind each other. then inside these layer is a div with position sticky that contains the text. You can use http://codepen.io to try the structure and then try to somehow do that with lay theme.