The closer you can stay to fresh foods, the better. Simple carbs are those that are the most refined and many tend to be made from white flour and/or sugar, which would include candies, cookies, white bread, pasta, white rice, etc. White potatoes are also often considered simple carbs, but should not be left out of a healthy diet because they have lots of vitamins/minerals (potassium in particular).
Dairy is generally considered a protein but also contains a lot of calcium, so yes, opt for the low/no fat varieties of milk, yogurt, cheese, etc.
Yes, simple carbs are from white flour, over processed foods.
Smart carbs tend to be whole grains, fresh fruits and vegetables. Basically things high in fiber are smart carbs.
I thinking that milk is a protein? Going with Skim or 1% is good.
I have much to learn myself yet but I do know that I have been basically following the Canadian Food Guide which highly promotes whole grains.