Just find an opponent, then start apprentice and select "new game" and then under game type select connect via the internet. Another screen will come up, it will ask you are you calling an opponent or waiting for a call it also shows your current IP, if you are waiting for an opponent tell them your IP number and they will call you (select "waiting for a call" and hit ok), if you are calling an opponent get their IP number and type it in the blank space then hit ok (one of you must be waiting for a call and the other must call otherwise it will not work)
It's a lot easier than it sounds.