when i am trying to listen to my webhook , which is a post request . how can i do that？

You should be able to just listen for it like you'd listen to any POST request. However, the fact that you sent a request to it and got a confirmation despite not writing anything to handle that request makes me think there's more going on. It sounds like this is something you're doing for work (judging by the 'QA' portion) so you might have to talk to them about how to route requests to your handlers.