How do "payloads" and "postbacks" work in EngageOne Converse?

From the bot’s prospective, you use ‘payloads’ and ‘postbacks’ to send something back to the server that can trigger another activity.
For example: If you are on a message and add a button of type postback (send data to server as if the user typed it) the payload is what the server will get. If the Button was YES the payload could be “do_yes_interaction”, then you have another interaction whose intent/when we receive is configured to expect “do_yes_interaction”.
UPDATED:  September 19, 2018