I am a medium to advanced AS3 game developer. I have experience with C#, and a little bit of Java.
I want to start making an online multiplayer game like Starcraft II. Obviously it will be more simple.
I have been googling for a while now to find out how to do this, but i'm actually only finding fairly specific tutorials, that I don't understand. I don't have any experience with programming servers, nor peer to peer. All my games have been single player or multiplayer with the same keyboard.

My question is: Do you know any tutorials/articles that explain exactly how to get started doing this. I could turn my pc into a server for example, but I don't know how to do it.

Just giving me some directions on where to start, would be a great help.

Thank you.