Here is a summary of the text: The article provides instructions on how to add overlays, such as logos or user names, to a web-based video chat using Twilio Video. The process involves creating a simple HTML page with a button that triggers the overlay when clicked. The overlay is achieved by taking the content out of the document flow and positioning it absolutely over the video. The article also covers how to add images or watermarks to the video as overlays, using CSS generated content tricks. Additionally, it discusses how to use Flexbox to define the layout of the container element and fix issues with responsiveness. Finally, it provides a solution for fading in the overlays once the video has loaded by adding a class and using transition properties.