One has nothing to do with the other. The DDE is the dining experience, where you get 20% off food, and you can either get it thru the mail with your DVC card, or you can pick up a temporary card over at Downtown Disney. Your AP is your admission to the parks, and I don't understand why you wouldn't want to activate it right away. At any rate, they can send a voucher thru the mail, but you activate it in person, at either the entrance to the park or at Downtown Disney, and you get a discount with your DVC card too.