I does anyone know how to create a survival multi-player server?

I do not mean the free build type server, I already have that.

Anyways I have just bought the game and me and my friend wanted to play an online survival multi-player I have seen it in youtube videos, so I know it is possible. But I can't find a tutorial or any help on how to make a server to play a survival multi-player.

If you can help it would be much appreciated! 

Thanks!