On webflow for this tricks is better to give some height (by padding is the best) - to the element (You see the animation only on publish site - but it hard to work with “non-height” item).
Summary
So again - create div → add some top/bottom padding (and bg if you want) → add id #wow - than initialize the plugin by id selector#wow
Also this is jquery plugin so wrap your code with doc ready (To avoid errors)