A Vonage Video publisher tutorial is provided, covering the creation of a web application that overlays text or an image onto a user's camera stream in real-time, and includes it in a video call session using the Vonage Video API. The tutorial requires several components, including a video element, canvas elements, and JavaScript functions to manipulate the video stream and add text or images to the canvas. Once the desired output is created on the canvas, it can be used as a source for a Vonage Video API publisher. The tutorial includes scaffold markup, code examples, and instructions on how to include the canvas in a video API session, hide elements, and publish from the second canvas.