Unless you are a
dvc member the only way to get the dining plan is if you purchase the Magic your way package. Packages include room & tickets.
If you really want the dining plan & depending on when you are traveling, you may want to call Disney to see how much it would cost for a package and you could just purchase one day tickets. You could use the ticket now, or save it for future use.
We are doing this when we go in Feb. (2 adults) I was going to book a room only, but knew we would be doing atleast one sit down meal a day & wanted the dining plan. We got in for the 7 for 4 promo with the $200 gift card upon check in. For us, I looked at the $200 gift card as paying for the tickets, plus about 1-2 days of our dining plan.