How to build and publish your Android app
In order to build your app, you'll need to create the login method with Facebook, then you'll need to create the Firebase and login method with Google+.
1 - Please follow the steps on this article.
Creating the Firebase account and file:
1 - Log into your Google account and go to http://firebase.google.com and create your project (or select it if you already created):
2 - Select Android
3 - Insert your package name and the SHA-1. (You can also obtain this on the App builder page on your site manager)
Obs: SHA-1 and the package name are separated by (;)
4 - Click Authentication on the left menu.
5 - click Login and activate Google.
6 - Download your .json like below.
Site Manager App Builder
Go back to your App Builder page on the site manager and upload the .json file you just downloaded.
Submission to Google Play
1 - Access https://play.google.com/apps/publish/ log in with your Google account. Click on + Create app.
2 - Pick up your default language.
3 - Fill in with your Google informations.
4 - On APK, send up the .apk you generated on the site manager, upload it and click Save and send to production.