Download it · load it · sign in.
Download ExtensionDouble-click the file you just downloaded. You'll get a folder named meet-live-transcriber-extension.
Open chrome://extensions, switch on Developer mode (top-right), click Load unpacked, and pick that folder.
Click the Scribe icon in your Chrome toolbar, then sign in with the same account you're using here.
chrome://extensions and switch Developer mode back on (or hit the reload ↻ on it). You stay signed in; nothing's lost.