The dining plan is awesome!! You can choose to eat at basically any restaurant on property!! Not all, but the majority!
I believe you must be staying in a Disney resort (not swan and dolphin, shades of green, etc.) and have a MYW ticket package!
The way it works is that you get per person each day:
-One counter service meal (includes appetizer, drink (non alcocholic), entree, and dessert or full buffet and gratuity/service charge)
-One Snack (There are signs all over Disney resorts and parks about what constitutes as a snack--basically, icecream bars, chips, drinks, apples, etc.)- They have to be under 4$ to qualify!
-One table service meal (appetizer, entree, dessert, and non alcoholic dessert)
There are some places that you can swap two counter service meals for one table service meal per person: for example, the dance shows, restaurants like citricos or narcoossees at the GF of Flying Fish at the boardwalk. Also, you are able to get room service with this deal (2 for 1)
As an annual pass holder, you aren't eligible for the
Disney Dining plan unless you have purchased MYW tickets separately. You can, however, purchase the Disney Dining Experience card which I think gives you 20% off of your meal at most restaurants on property. I want to say that is around 60$ but you can use it for a party up to 10 or so! We went to the Chefs Domain at Citricos for a thank you dinner during the week of our wedding and was able to get that discount. It saved us close to 200$!
I hope this helps!
