To use GPT (Generative Pre-trained Transformer) in a chat application, you will need to set up a chat server and integrate the GPT model into it.

Here are the general steps you can follow:

1. Set up a chat server: This can be a simple server that uses a protocol such as WebSocket to facilitate communication between the chat client (e.g., a website or mobile app) and the server.
2. Integrate the GPT model into the chat server: You can use a library such as OpenAI’s openai library to load the GPT model and use it to generate responses to chat messages.
3. Connect the chat client to the chat server: The chat client (e.g., a website or mobile app) should connect to the chat server using the appropriate protocol (e.g., WebSocket) and send chat messages to the server.
4. Handle chat messages in the chat server: When the chat server receives a chat message from the client, it should use the GPT model to generate a response and send it back to the client.