Hi Sanjyot,
Thanks for posting this on the forum!
You can use multiple stacks whenever one stack is not sufficient. Usually these are pretty complex pages.
Here's one example - imagine you have an entire quiz built onto a single page (your questions are all in one stack), and you want to have your feedback in a different stack.
Or if you have a complex interaction with lots of moving parts (intro, feedback) and popups throughout.
Here's a video showing you examples of these -
https://share.smartbuilder.com/public/support/multiple-stacks-why-and-how.mp4Let us know if you have any questions!