you already have 6 pack abs, it's just covered with a layer of tummy fat. First and foremost it's nearly impossible to get your six pack showing in 7 days. If you do your eating habits would consist of like 3 apples per day, and drinking at least 2 gallons of water per day.
The key is to eat right. If you know it's bad for you then don't eat it. But this has to be a lifestyle change and can't seem like a chore. Once it seems like a chore that you have to eat right, you psychologically already failed.
Also just be consistent. The best way I can tell you to start seeing results is by eating 5 small meals perday. Include fruits and vegetables in all of those meals. Lean chicken, brown rice, etc. Drink at least 1 gallon of water per day. Work out 5 days a week. Do all exercises not just ab workouts. You want to shed overall body fat. I mean what if you had six pack abs but fat legs and skinny arms? Plus your body works in sync with other muscles, when one muscle is strong so are all of your other muscles.
Try this out. Everyday you go to the gym always target every muscle group. Do ab workouts, arm workouts, leg workouts, back workouts. Now inbetween every workout, let say you just did legs and are about to go do arms. Right after legs, go to the treadmill, put it on an incline of 2.5. And push yourself as hard as you can for 3 minutes. This way you burn more calories and keep your heart rate up for when you hit your next exercise. Do this inbetween every workout and you'll start to see an overall body within 2 weeks. But you have to eat right!
hope this helped, all the best!