If you sit in a chair and don't do anything your body needs a certain level of calories. During exercising you must not only add more calories to your diet to make up for those lost in exercise, but also extra for your body to build muscle. Protein shake are a way to add extra calories in the form of protein, carbs, and fat. So eat normally then throw the shakes in as a "snack" after workouts and before sleep.
Make sure you workout of the supplements will just go towards making fat. Some fat will come with the extra caloric intake as well as muscle, but thats why most people do a "building phase" to get their desired muscle mass....then a "toning phase" to trim the fat off and really show muscle definition.
Workout should include high weight at low reps (5-8) for multiple sets.
Hope this helped and good luck!