How to add new project to you current FCM project?
This guide will show you how to add new project to you current FCM project. This example will show you how to add new Android app to current FCM project.
1.) go to https://console.firebase.google.com/
2.) Select you project

3.) Click -> Add Another app button (1) and select app type (2)

4.) enter your Android package name (1) and press -> REGISTER APP button (2)

5.) Download and copy (replace) "google-services.json file" file to directory "YouAndroidProject/app/"

6.) Skip Next Step and press -> FINISH