With so much information out there, I'd like to offer a simple explanation of carbs.
Good carbohydrates come from plant foods. Whole foods, as close to the way they grow in the ground, are good carbs. These carbs are good fuel for your body and they are easy for your body to digest.
Bad carbohydrates are processed foods. If your food comes in a carboard box, it's processed food. White flour and sugar, the main ingredients in those processed foods, are empty calories. These highly processed foods are stripped of nutrients, have very little nutritional value, and are packed with calories that do little to support health.
So, next trip to the grocery store, shop the perimeter. This is where whole foods are found. Avoid the interior of the store with all the boxed, processed, so-called foods that offer little nutrition and lots of calories.