Nutritionist told me to eat 1200 calories a day and walk for 30-45 minutes everyday. im a little confused, is the 1200 calories the amount after burning calories from walking? or is it the amount i have to reach with walking? like eat more and burn?

Usually the number of calories refers to total calories ingested per day, in order to lose weight a negative calorie balance has to be maintained. Best would be to clarify with your nutritionist directly otherwise.

A normal adult female should be taking in about 1800-2000 calories per day. If your Dr recommended cutting the total number of calories you take in per day to 1200, and walking 30-40 minutes daily, follow these instructions. It does not mean to subtract how many calories you burn from that a higher number of calories in order to reach 1200 total.