Hi Alicia,
Your vacation is coming up so soon, you must be getting very excited! Having a
Disney Dining Plan means that you have already paid for your food at Walt Disney World, which is great. Your 8-year-old will have a child's dining plan, which means that he or she must order from a children's menu when available. Your 11-month olds will not have a dining plan; however, they are welcome to eat from your or your older child's plate if there is something that they like.
If you visit the Disney Dining Plan site that I linked above, along the right-hand side, you will see that there are many different types of dining plans. Clicking on the link for your plan will download a brochure with participating restaurants. Which plan you purchased will determine which types of credits you receive. For example, the quick-service dining plan gives each guest on the dining plan two quick-services meals and one snack per night of your stay. The regular dining plan affords each guest one table-service meal, one quick-service meal, and one snack per day. All of the dining plans come with one resort refillable mug per guest over 3 years old. These refillable mugs are used at your resort for refills on drinks such as soda.
The meal and snack credits are allotted per night of your stay rather than per day. Also, all of your credits will be available to you on your first day, and you do not have to use them evenly each day. So, for example, if you have the regular dining plan but want to eat two table-service meals on one day and two quick-service meals on another, that will work.
For more information, the unofficial site disneyfoodblog.com has a great frequently asked questions page about the dining plans that you can access by heading to their website and searching "dining plan."
Please do let us know if you have any further questions, Alicia!