Thinking of the Atkins diet....?

I have a lot of weight to lose! Im like too embarresed to actually post my stats. But i will say that i am 13. Well i did atkins like a year ago and lost like 30 lbs. gained it back-plus more. well so can anyone explain the steps to me of this diet. All i know is 20 carbs a day with lots of water. Unlimited chicken. any help will be appieciated.