If you're still unsure on how to get started with React Native, then check Wiktor Mociun's comprehensive introduction:

Going mobile with React Native blog post

When Facebook announced React Native I was amused. It is my chance to start developing mobile applications. I already know React and I can write most of my code using it.

If you haven’t seen @Vjeux talking about React Native on React.js Conf, you should definitely check it out before.

I want to share my path in making simple application for iPhone. I believe that experience should be enough to start creating bigger apps.

fair_pizza code on GitHub