I don't understand a thing about the Card, Conversation, Confirmation formula for user stories. I don't understand if the conversation and confirmation part must be written down or they remain as a dialogue, in particular the CONVERSATION part. To be clear: is it right if a write down ALL these things in user stories? (see example below) Or do I have to write down only the CARD part?
Example:
CARD As a user of a coffee machine, I want to be able to purchase a beverage.
CONVERSATION - The user will not be able to purchase a beverage if they do not deposit enough money into the CoffeeMaker - A user's money will be returned if there is not enough inventory to make the beverage
CONFIRMATION 1 user introduces the amount of money needed to purchase the beverage 2 user selects the beverage 3 user gets the beverage