Stack overflow is the holy grail for sure
As i mention before it will take a long time for me to decompose your project and get my head around how all your interactions are setup.
But the idea would be to have different section which you can scroll of an arbitrary size and use them as trigger fo scroll into view and scroll out of view. It can be really tricky thought as you will need a sort of reset of your animation for it to work again on next scroll.
Another way would be to have only 1 big section and use the while scrolling in view to make all your different sections and elements animate depending on the scroll position.
I recommend this project to have a look at the way he’s setting up interactions
And this is the most recent workshop from pixel geek which will give you very good tips and trick to achieve this kind of design.
Again if you were to replicate your design on a small scale like 2 sections in a new shared blank project would be easier to demonstrate.
Also enjoy the showcase as there is a huge amount of good projects to breakdown.