This statement refers to the fact that, there are no rules like "you should put a O to block X.X" and things like that. Inside the program there is just the rul

This statement refers to the fact that, there are no rules like "you should put a O to block X.X" and things like that. Inside the program there is just the rule to understand if the game ended and who won. In the NN there is nothing at all of course, it's just random weights at start.