Hi Behnam,
Your action server should be using the utter_message and SlotSet calls to send a message and set slots.
You can retrieve the user utterance text by calling tracker.latest_message.get("text"). You’ll find an example of this in our Sara demo bot here.
You can find metadata from the slot in the tracker event. There’s an example here.
You can get the value of a slot via tracker.get_slot("slot_name").
Greg