Online Game Development

Hii Raywenderlich
I want to make a game like Teen Patti (URL of this Game:- https://play.google.com/store/apps/details?id=com.octro.teenpatti). So Please help me that how i create basically I think about this game and finally i think that I should use json and as chance come then i should notify by Push notification.But unity not gives any method for generating device token for this i am making a plugin in Android studio . You have any best suggestion for me.