message: Add note about monorepo
diff: @@ -22,7 +22,12 @@ plugin in this example.
  yarn workspace app add @backstage/plugin-circleci
  ```
  -2. Add the plugin itself:
  +Note the plugin is added to the `app` package, rather than the root
  +package.json. Backstage Apps are set up as monorepos with
  +[yarn workspaces](https://classic.yarnpkg.com/en/docs/workspaces/). Since
  +CircleCI is a frontend UI plugin, it goes in `app` rather than `backend`.
  +
  +2. Add the plugin itself to the App:
  ```js
  // packages/app/src/plugins.ts
  