How to make my app to trigger specific action based on url link clicked in another website

Is there any simple example for a method triggered by url link?

I found this in the forum " POST method from HTTP blog - method not supported ", but it still difficult for me to understand how does it work (I am still a beginner, and I learn as I go :blush:), the easiest way for my me to understand is to see a live example.
I created this app

https://anvil.works/build#clone:V7MZTITY6PNEHW5W=LKLNODVDPLJ2JUHHUML5BKWR
Hopefully with some guidance I can accomplish my goal

the link to the app: https://clumsy-petty-peafowl.anvil.app/

Thank you for your help!