How exactly does deficit work?

I'm 24F and 5.5 ft and about 165 lbs and on the TDEE calculator I got 2100 calories (I chose light exercise - office job but dancing 2 times a week, lifting weights 3 times and walking 5-10k steps a day). Now I'm pretty confused on how the deficit would work. I wanna lose 0.5-1kg a week (yes I'm in a big rush atm) so how much am I supposed to eat daily to lose weight: 2000 calories with exercise or 2000 with exercise minus the caloric deficit? For example if I wanna have a deficit of 500 calories does that mean I have to eat 1500 calories and exercise or can I eat for example 1900 and burn off the 400 with exercise and still lose weight?