Calories help.

When you signed up you put in all your current height, weight and age. This is used to calculate your resting or basal metabolic rate which is the amount of calories you can consume in one day (that your body burns just by being alive) without putting on weight. Then it has you select what you do for a job, whether it's sedentary or lightly active, etc. If you select sedentary, that gives you your restic metabolic rate. The cutting 500 calories a day thing can be done by just eating less or exercising or a combo of both. If you somehow cut 500 calories from your diet every day, after 7 days you should have cut a total of 3500 calories. One pound of fat is equal to 3500 calories, which means you would be cutting one real pound of fat from your body every week which is a completely healthy and safe way to lose weight. The way I track how many calories I have cut is to look at the remaining calories, which if you are under for the day shows green, and over shows red. If you have 500 calories remaining for the day, you are good to go on the one pound per week weight loss.

It depends on how you're set up.
My home > settings > update diet / fitness profile
If you're set to lose weight (0.5, 1, 1.5 or 2 lbs per week) then your daily calorie goal already contains the deficit for you to lose weight (assuming you didn't run into the minimum 1200 calories that MFP won't set anyone below) Your planned exercise isn't included as part of your daily calorie goal. WHEN you log the exercise as having been done (exercise > exercise diary > cardio > add exercise and enter the minutes you performed the activity) you'll have those calories added to your day, if you're set to lose weight you CAN eat those calories and keep your deficit at the desired level....

Don't mix n match though...
you can either use MFP with the weight loss set in your fitness profile, then netting your calories
OR
set your fitness profile to MAINTAIN weight, and use your exercise to build your deficit for weight loss.
OR...
lots of ways to use it, just make sure you pick one and stick to it, you'll see things such as TDEE less 20% for weight loss etc. Just pick the way that makes sense.
MFP is designed to give you a daily calorie goal to lose weight through your eating habits alone. When you log exercise you have burned more calories taking your deficit below the level for the weight loss you set, you CAN eat those back (if you're comfortable with the burn value) and still lose weight.

you try to eat whatever the calorie goal that MFP sets for you a day, do not subtract 500 from it. It is ok to be under as long as you try to eat at least 1200 calories a day. After you lose say 10 or 15 pounds MFP will ask you to update your goals with your new weight and it will change your calorie goals for you. So if it says to eat 2000 calories you should be trying to eat close to that number everyday. I hope you understand what I am trying to say.

I still dont get it. I just changed my profile for my activity and now my calories for daily is, 2040 a day! Also I see that there's one lb lose a week is recommend so I leave it as it is. I put in 15 mins of walking, it add more calories. Over 2000 aday! I'm so confused. Simple question, how much of calories do I follow everyday? 2000 or take 500 away from it, 1500 then if I exercise add 200 then it'll be 1700 a day? Please help me understand this in simple English! Please be bear with me. Thanks.

When you told MFP that you want to lose 1 lb a week, it already took the 500 calories off what you would need to eat to maintain your weight. So, the target it gives you is what you should eat. And yes, it does have you eat more when you work out. The deficit is already built into your calorie goal, so it gives you the extra calories to keep you at that 1 lb a week rate of loss.

Depending on your height, weight, and activity level, 2000 isn't surprising at all. It set me at 1850 (and I eat back most of my exercise calories) and I've been losing 2 lbs a week. If I set my goal to 1 lb a week, my target would be 2350 a day and I have no doubt that I would be losing (just more slowly).

Just eat what it suggests right now. Don't try to make it more complicated until you get the hang of that.

When you signed up you put in all your current height, weight and age. This is used to calculate your resting or basal metabolic rate which is the amount of calories you can consume in one day (that your body burns just by being alive) without putting on weight. Then it has you select what you do for a job, whether it's sedentary or lightly active, etc. If you select sedentary, that gives you your restic metabolic rate. The cutting 500 calories a day thing can be done by just eating less or exercising or a combo of both. If you somehow cut 500 calories from your diet every day, after 7 days you should have cut a total of 3500 calories. One pound of fat is equal to 3500 calories, which means you would be cutting one real pound of fat from your body every week which is a completely healthy and safe way to lose weight. The way I track how many calories I have cut is to look at the remaining calories, which if you are under for the day shows green, and over shows red. If you have 500 calories remaining for the day, you are good to go on the one pound per week weight loss.

Have you set up the program up to maintain your current weight? You'd need to do that for the math to work out the way you're doing it, as the 500 calories you're leaving behind every day is in addition to any calorie deficit the site has already calculated for you.