Hi Lynne, Disney's Quick (counter) Service Dining Plan includes 1 entrée, 1 dessert, and 1 non-alcoholic beverage.
Guests may get a side with their entrée if it is listed as a "combo meal" at the restaurant. For example, if you see a burger with fries on the menu board, that’s what you get. However if a you are getting a salad for example, those do not include a side, so you would need to use a snack entitlement to get fries with this.
Essentially, you need to take the time to look at the menu at the restaurants and purchase a "combo meal" if you are wanting a side dish with your meal.
Hope this helps and that you have a magical vacation,
Kaylene