This repositery contains the projects associated with this video: https://youtu.be/KZadYD62RnA.
You can find the initial Unity project in the initial directory, and the final Unity project in the final directory (how orginal!).
I also put the link.xml file, that you need to put in your Assets folder if you want to build on an IOS device.
If you use one of these projects, don't forget to create your own App Id on Facebook and your own identity pool on AWS Cognito, then update this information inside the project.