1. Define the extension's functionality and design the UI

• Decide what the extension will do and focus on narrowly defined functionality
• Sketch out the UI and layout for the popup, options page, and other components
• Plan the user's journey through the extension and different screens
• Prioritize key elements and establish a clear visual hierarchy
• Design a recognizable icon that represents the extension's purpose[1]

2. Read the Chrome extension documentation

• Review Google's documentation for Chrome extension developers
• Learn about development basics, design guidelines, debugging instructions, etc.[1]

3. Create a developer account

• Create a Google account specifically for Chrome extension development
• This account allows publishing the extension to the Chrome Web Store[1]

4. Create a project directory and manifest file

• Create a project directory to store all the extension files
• Place the manifest file in the root directory
• The manifest.json contains information Chrome needs to install and run the extension
• Define a V3 manifest which has more features than the deprecated V2 version[1][4]

5. Load and test the unpacked extension

• Enable "Developer Mode" in chrome://extensions
• Load the unpacked extension from the project folder