Hi,
I will try to define my problem statement in following steps, I have uploaded the images as well for better understanding
Main transition section (only left part) will scroll up and settle at top (pinned), please refer to step-1.jpg
Right image will be scrolled up till left part, please refer to step-2.jpg and step-3.jpg
When the above transition done, then "Yes, Hello" will appear at centre of the page, please refer to step-4.jpg
one the "Yes, hello" appears then all these will scroll up together, please refer to step-5.jpg