Notification with smartThings api

i am developing notification with smartThings api

i want to make notification with smartThing api Rules thru Postman

i google it for several days and search for official documents from Samsung smartThings

but i cannot find that how am i going to send body in postman

for example
when doors open, notify me that ‘the door opened’

I’ve been trying to get Notifications working via the Rules API for a long time but I just can’t get the syntax right. Every now and again I have another go in the hope it will suddenly become clear but it never does so I am stuck waiting for it to be documented.