message: docs: update auth sign-in setup docs
diff: @@ -56,18 +56,15 @@ allows a single auth backend to serve multiple environments, such as running a
  local frontend against a deployed backend. The provider configuration matching
  the local `auth.environment` setting will be selected.
  -### Adding the provider to the sign-in page
  +## Using an authentication provider for sign-in
  -After configuring an authentication provider, the `app` frontend package needs a
  -small update to show this provider as a login option. The `SignInPage` component
  -handles this, and takes either a `provider` or `providers` (array) prop of
  -`SignInProviderConfig` definitions.
  +If you want to use an authentication provider for sign-in, as opposed to just accessing external resources, you'll need to configure that in the your app as well. This is done by provided a custom `SingInPage` component to the app, which will require the user to sign-in before they can access the app. Note that this is does not block access to the app, which you can read more about [here](./using-auth.md).
  -These reference the `ApiRef` exported by the provider. Again, an example using
  -GitHub that can be adapted to any of the built-in providers:
  +If you want to use can use the `SignInPage` component that is provided by `@backstage/core-components`, which takes either a `provider` or `providers` (array) prop of `SignInProviderConfig` definitions. These reference the `ApiRef` exported for the provider.
  +
  +Again, the following example for GitHub shows the additions needed to `packages/app/src/App.tsx`, and can be adapted to any of the built-in providers:
  ```diff
  -# packages/app/src/App.tsx
  + import { githubAuthApiRef } from '@backstage/core-plugin-api';
  + import { SignInProviderConfig, SignInPage } from '@backstage/core-components';
  