How do i start?

Hi im new at this, ive been working out for a while and havent seen anychanged on the scale.

im a 27 years old female, 130lbs and 5 foot (152cm). I go to the gym at least 3-4 times a week with a minimum of 30 min of cardio. My upper body is lots of muscles but lower as mostly fat..trying to loose 15lbs and when i try to set my goals i to the apps it says i should only eat 1240 calories which to me is low !!! And how do i know my macro like 40p/40c/20f ? I know everyone is different but i dont wanna loose the muscle i already have. Ive been ready a lot lately and it is so confusing..can someone help me ?

i do i know how many calories a day ? I know there are the NET calories and all but it seems weird cuz we dont really how muh calories i burn whole weight lifting !! Is there a number i could eat everyday without having to substract the calories i burn while excercising?

Thank you