This tutorial provides a step-by-step guide on how to integrate OpenAI's models with Twilio Voice using ConversationRelay, a product from Twilio that enables real-time, human-like voice applications for conversations with any AI Large Language Model. The integration allows for a fluid, event-based interaction and fast two-way connection. To deploy this tutorial, users need to have Node.js installed on their machine, a Twilio phone number, an OpenAI account, and the ngrok tunneling service. The code is written in Fastify, a framework that quickly spins up a server for both the WebSocket and the route for instructions. The server connects to OpenAI using the API key stored in an .env file and sets up a WebSocket app to communicate with ConversationRelay. Users can run the server and test it by dialing up the number on their phone, hearing their customized greeting, and interacting with the AI. However, this simple demonstration has limits, including latency issues when generating a lot of text from the LLM, and the authors plan to show how to improve these in future posts.