Exception chat handelling

Hey guys, I am using rasa with http api service and testing it with botframework(v4) - Node.JS. I want my bot to handle a situation where if text/sentence is not lying under any intent. It should give some particular response like “Sorry, I didn’t understand”. How can I apply these thing in my bot?

You need to add fallback policy and define an action for that.

https://rasa.com/docs/core/master/fallbacks/

Can the fallback be configured from terminal?

Cool, but what does one use as action in the domain?

I am using HTTP API to create my bot so please can you guide me how to link fallback with bot training data.