How to add new data to Firebase database in android studio? : The problem itself is more complex than the question makes it seem, at least to me. 
[My database;][1]

[1]: https://i.stack.imgur.com/hBVEZ.jpg

The problem is that I am fairly new to using Firebase for my android app and I do not know how to add an entirely new User profile here. For example, if someone were to register, and it would then add a new "record" at "2" and so on. How do you do this? 