Custom Sign-in

Hi there.
Is there a way to use Custom form as Private sign-in?
Like I have a main screen that has two buttons:

  1. One is for entering the app
  2. Another for new user to sign-in

The entry button only show if the new user had sign-in.
Also if not, only the Register button appear.

When you use the email as a way to enter the app, it gets register somehow and the user is not asked again for the sign-in.

If the user has not logged into the app, then theoretically I don’t think you can know if they are a “new” user or not, unless you store something on the back end like their IP address. You would have to ask for their permission to store it, but I think it’s too complex to set it up like that.