Hi David... The first you have to do is cut out sodas and sugary drinks and treats, chips and other snacks. Just doing that will make a huge difference in getting started on a weight loss journey.
You should talk to your parents and ask them to make sure there are plenty of fresh foods for you to snack on, such as carrots, celery and other raw veggies and a few fruits, so you don't have to rely on chips and processed foods.
Also make sure you get some exercise every day. Even if you just go for a 20-30 minute walk, it's better than not doing anything. Most sports, riding bike, etc are excellent exercise. Exercise builds muscle and muscle burns fat, which helps you lose weight.
Yes what he said by cutting out sugar an soda you'd be amazed how fast you could slim down even just a little bit, I've done this I've had friends that done it an they look amazing! Try more fruits an veggies drink more water lot of times when we think we're hungry we also just need water it can fill that void an help you eat less as well.