How to gather stats from online games of my game?

Hi, I am currently trying to find a way to get stats from the hosted servers of my game (advanced steam subsystem) to me, to gather for example round wins of each side, or kills/playtime of each classd to get an idea how to balance the game.

But I have no idea how to get the values from the hosted servers to me, I guess I have to use an own webserver where the clients that hosted the game can communicate with, but I dont know where to start. Any ideas or experiences you can share? Thanks a lot!