Need help with scroll interaction

Hello, I’m running into problems while trying to replicate an effect I found on a non-webflow website. I’ve tried different options, watch scroll tutorials at no avail. I wonder if someone can help me clarify and understand what I’m missing. This is the original site I’m trying to replicate:
And here’s my read-only link, I appreciate any reference or link to be able to figure this out, it’s driving me a little nuts to be honest,

Thank you,