UGS and Backend Server

I know unity gaming services launched and has its own authentication…I am just looking for something super simple. I want the player to log into Google Play Games on Android and then get a token and send it to my server so that I can get the players ID and identify them from their google play account…Does anyone have any simple video tutorials on this? It should be easy but i cannot find any tutorials that work…

Or does UGS do this now in a simple way. Any help would be greatly appreciated thanks.

The manual has a step by step tutorial for each service.