Add some code and functions to an already created Shopify Store

It’s very easy: I need this ([login to view URL]) to work like the "Experiencias” section on https://zensual.es. It doesn’t need to be the same way, I mean, if it’s possible to do so by using only CSS and avoiding using JS to make it faster, then better. I already have the HTML structure as you can see, I just need the CSS/JS magic to make it work as in zensual.