Using 3rd Party APIs

I have a couple of game prototypes built and feel comfortable with the core concepts of Unity. However I would like to have a social component and am struggling to build it myself.

I would like to have leader boards at a minimum. It looks like there are several services (GameSparks, PlayFab) that can help streamline this across platforms. The have decent documentation, yet I’m still struggling.

I’d like to learn how to accomplish the following:

Authenticate a user via Facebook
Track users High score, best word, etc
Have leader boards based on users Facebook friends

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