SO CONFUSED PLEASE PLEASE HELP ME!?

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Hello everyone,

I have been a member on MFP for a couple months now but have only really started to use it, in the past week.
I'm sorry if I sound uneducated and silly but I am so confused about deficits, BMRS and everything, My mind just simply can't get around everything, No matter how much research I just don't get it. Again I apologize for sounding silly.

I am 19, Female, 6ft (1.82m ) and hoping ultimately to lose 2lbs a week.

GOAL: 1630 a day. I workout 6 days a week at a gym, Usually 2 hour cardio workout and Strength Training 3 days per week. I eat super healthy, usual Veggies, Fruits, Chicken and ONLY water & Green tea.

Now could someone please explain Calorie Deficit in simple terms. Am i Suppose to eat exactly 1630 calories, is A Calorie Deficit Built in? When i do exercise Do I have to eat back my exercise calories, If don't will I not lose?

Thank you Very much