You can enable authentication for your app via the Auth section in the global toolbar.
When you choose an authentication type, the relevant pages are installed for your app.
Initial view is a fullscreen page that is opened first, before the user is given access to the rest of the app. In most cases, it is used to show a login form.
When your app has authentication enabled, the Auth section lets you choose which page is used as the initial view.
It has its own navigation stack, so you can e.g. open a registration page with Open page, just like on any other page in your app.
To dismiss the intial view and open your app, use the Dismiss initial view flow function. To return to the intial view, use the Return to initial view flow function.