How to write a simple chat program using UDP and VB6

You probably won't find exactly what you want to hand in, but a simple google gives you all the components, used in different projects: chat program using the Winsock control with VB6 and UDP - Google Search[^]
So start with those, and get the communications working first without worrying about any practical user interface.
Then consider what you need to transfer and add that.
Then start thinking about the UI - which should be pretty easy by that stage.