I'm actually looking into this at the moment, snooky and I'm confused as Instagram seems to limit those and to "forget" favorites after a while. The documentation is also lacking, so I have to take a look how the official apps are doing this. Still working on it, but I'm not getting anywhere at the moment. Paginating it is easy, but getting all the data seems hard
To summarize: The Instagram API does not allow signing up / creating new users. You therefore need to create your user with one of the official apps, either on iPhone or Android.
One way around this is Bluestacks, which allows you to run the Android app on your desktop.