The codelab has the full instructions, but as a quick start, you can do this.

1. In your terminal, run:

firebase emulators:start --project demo-codelab-nextjs

2. Copy the file lib/firebase/config-copy.js to lib/firebase/config.js and fill in the values from the Firebase console.

3. In a new terminal tab/window, run:

npm i
npm run dev

4. In your browser, open the URL: http:https://localhost:3000

1. While on http:https://localhost:3000/ within your browser, click the "Sign in" button in the top right corner and sign in.
2. In the dropdown menu in the top right menu, select "Add sample restaurants".