This section is only necessary in case you wish to be able to receive push notifications in your React-Native app.
Push notifications on Android are managed and dispatched using Google's FCM service. The following installation steps are a TL;DR of Google's FCM setup guide. You can follow them to get FCM integrated quickly, but we recommend that you will in the very least have a peek at the guide's overview.
To set FCM in your app, you must first create a google-services.json file. If you have no existing API project yet, the easiest way to go about in creating one is using this step-by-step installation process;