Its good you've set a goal and are looking to find out how to achieve it! However losing 15 pounds in a month is unrealistic and unhealthy. Did you know it takes about a year for your body to adjust to losing 10 pounds? It's important to remember weight loss is a marathon and not a sprint. In order to lose weight and keep it off, you shouldn't look at it as weight loss but a way to become healthier! The key to doing so is no secret-- eat a variety of healthy (organic if possible) foods ( tip; it helps to stay away from packaged foods which are high in calories -- remember calories aren't necessarily bad, it's when they're empty that they are, this means they don't fill you up and promote excessive eating. That said don't be afraid to splurge occasionally ) work exercise into your life (eg. Walk when possible, join a sport, gym or class or even workout on your own).
As for abs, you should find workouts that target your core! You can do so by searching ab workouts online, YouTube is full of great videos (I really like blogilates, livestrong woman, Tara stiles) or even finding apps ( I like nike training club because they have 15 minute focus workouts ! I especially like these methods because they're free and fun.
I encourage you to calculate your BMI (body mass index) , make a healthy/realistic weight loss goal and go from there.
Here are some tips for healthy weight loss:
Eat well ( organic helps-- look for healthy recipes, they don't have to taste bad to be healthy!)
Exercise often (at least 3 times a week)
Drink lots of water
Treat yourself occasionally
Research (I recommend the documentaries Clean, Sugar and Food INc as they provide insight into the food industry)
Find a community ( this helps encourage/ support and motivate)
Don't think of it as weight loss, think of it as a lifestyle change (this will help you get healthy and maintain any changes!)
I hope this helped in some way and I didn't come off as too preachy! :)
Be patient and safe, you can do it!
I lost 12 pounds in 24 days by doing hcg injections once a week! I do 20 min of cardio a day