A pre-requisite to start with React-Native is to have a deeper understanding of React Ecosystem. I would suggest getting the basics cleared about React Hooks, Context APIs etc. from the official React Docs.
Once you are done with it, configure your local environment for targeted platforms, as mentioned in Getting Started Guide in React Native Docs.
Now, You can either start learning by reading official docs or I personally suggest this udemy course by Stephen Grider: The Complete React Native + Hooks Course 2020 Edition
Further, to stay updated with React Native Trends, follow this bi-weekly newsletter here
Finally, if you still have some questions, feel free to reach me out on my twitter handle: @pulkitkkr0