Confused about Calories VS Fat and Calories before and after

71Hoops

I admit I am a bit confused with regards to my starting calories, carbs, fat, protein and then how it increases as I add my exercise. It appears I am allowed much more after adding exercise but is it possible to lose the 2lbs per week if I use all the calories, fat etc? Shoud I be sticking to what I am allotted prior to adding exercise and then the exercise credits is how I will lose the weight? What if I have calories left but go over my fat? Any advice is appreciated.