I have reached my goal. I have been following Plan 1. What plan do I follow to maintain my weight?

you need stabilization plan 1. It is a 6 week plan where you keep adding food every week. Once your body weight is stabilized, you eat the same portions for rest of your life to maintain your goal weight.Every person is different so it is hard to say what portion is going to work for you.
I was on plan 1 and ended with 3.5P, 3S,3 F, 2D , 3 Fats and Unlimited veggies