Hi, Colleen! You have it correct, included with the Disney Dining Plan, adults get an entree, dessert, and beverage, the children get the same but also a children's appetizer.
The difference between the two is the menu selection. The children's appetizer selection on their menu will not be the same choices that are listed on the adult menu. For example, on the menu at the Grand Floridian Cafe, an adult may choose to add on (at an additional cost) Mushroom Ragout or a Caesar Salad. The child appetizer choices (included) are carrots and celery sticks or a cup of chicken noodle soup. Think of it as a complete "kids meal" with a kid-friendly appetizer.
For a complete explanation of the Dining Plan, click
HERE. If you scroll down to page 3, you will see exactly what is included with each meal as part of the Dining Plan.
If you would like to see the menus, go to
www.allears.net and click on DINING. For Advance Dining Reservations, call (407)WDW-DINE when you are 90 days out from your vacation. Have a great time!