If you only have a single request, you can make a request to the CityFALCON action through Google Assistant. To do this, you can say Okay Google, tell CityFALCON to tell me the top stories. But if you want to make several requests at once, such as hearing about different topics or managing watchlists, it may be smoother to launch the Action.
To launch the CityFALCON Action, say Okay Google, let me talk to CityFALCON. The CityFALCON Action will start and tell you that you are now speaking directly to the app. This way, you don't always have to preface your requests with Okay Google, tell CityFALCON to ... but can just use the various voice commands available for CityFALCON, like What are the top stories for My Stocks watchlist.
Whenever you want to exit CityFALCON, you can say Stop, and control will be returned to Google Assistant. Then you can use other Actions.