This tutorial demonstrates how to make phone calls to a Dialogflow agent using a Vonage WebSockets integration, allowing developers to build conversational user interfaces with natural language understanding capabilities. To accomplish this, users must create a Dialogflow agent, set up a service account for authentication and access control, and integrate the Vonage Voice API with the Dialogflow Reference Connection. The tutorial covers various deployment options, including ngrok and Heroku, and provides step-by-step instructions for setting up the Dialogflow Voice API Sample Application. Additionally, users can improve their Dialogflow agent by adding intents, entities, and responses to create a more conversational experience. The final step involves calling the phone number linked to the Voice API application and interacting with the Dialogflow Agent to test the entire setup.