The narrator introduces Module 1, focusing on a quick start Chrome extension build. Chrome extensions are composed of HTML, JavaScript, and CSS. Key components include the manifest file, content scripts, service workers, pop-ups, and option pages.

The manifest file is a JSON file describing the extension's components, permissions, and details. Content scripts are JavaScript and CSS files injected into web pages. Pop-ups appear when clicking the extension icon. Options pages open in new tabs. Service workers (formerly background scripts) run in the background without a UI.

There are two manifest versions: v2 and v3. New extensions must use v3. The transition from v2 to v3 began in 2018, with complete phaseout planned for 2024. Migration involves updating the manifest file, converting background scripts to service workers, and ensuring API compatibility.

The narrator will guide viewers through building a simple Chrome extension called "BBC Dark Mode" in the next lesson. This extension will convert the BBC website to a dark theme. A more complex extension build will follow in subsequent lessons.