Using Game Center in Cocos 2dx project

Ive made a game and i just want a global leader board of scores using Game Center and the GameKit framework.

I know you have to call the objective c code through a class that allows mixing of C++ and objective c.

Im just looking for a full tutorial in how to do it all. I cant find it anywhere.

Any help would be great thanks!

You can call obj C function from C++ code and vice versa, just need to declare the file as mm extension

Are there any tutorials that explains exactly what to do?

Thanks