This post is part two of a three-part series on how to build a custom Daily video call overlay app in Electron using daily-js. The key points covered are setting up the tray window, creating a join form and handling user input, joining a Daily video call, displaying local call controls, participants, and handling events such as leaving a call or toggling the microphone and camera. The code sets up an Electron application structure with main process and preload scripts, uses daily-js to create a Daily call object, joins a video call, handles participant updates and removals, and updates UI elements based on the state of the local participant and remote participants.