Integrating Firebase Analytics with Unity

I made an app (for Android and iOS) with Unity and I'd like to use Firebase Analytics on it.

What should I do in order to log events?

What I already did:

  1. Downloaded Firebase SDK and imported FirebaseAnalytics.unitypackage into my project
  2. Created a new project in https://console.firebase.google.com/u/1/
  3. Downloaded google-services.json and imported into my project

What I don't know:

  1. Do I need to make any other configuration or create a new project for iOS?
  2. What kind of C# code do I write in order to start Firebase and log events?
  3. I already used Firebase once in xcode and I remember the App ID was necessary, is it?

I wrote a code just like this but it didn't log my events.