To demonstrate the various ideas related to onboarding, we will create an Android app that is using Fabric for Twitter authentication and Firebase SDK for phone authentication. You can use Firebase as well for Twitter authentication, but the one that Fabric is offering is more convenient to use.

We will name this app, Tell a Story. Using this app, users can write a story together. Anyone can read the stories that people create, but, if the user wants to contribute to the story, he needs to sign-up using Twitter or his phone number. Let's start simple with a couple of wire frames that will explain the exact flow of the app:

The user lands on the introduction view when he opens the app for the first time. This view contains a clear explanation of why he should want to use the app and what it is about. There are two very clear call to...