You don't change chlorine, you add it. I used to know the amount recommended for residential(lower than for public pools), but haven't had a pool in over thirty years. We "vacuumed" weekly, topped it off if it looked like the intake was gonna start sucking air soon, skimmed leaves/debris as it showed. Tested weekly normally, but if we were going to have a bunch of people over, we'd test the chlorine level the day before and the day after.
You don't have to use chlorine, there are other chemicals. If I had a pool now, I'd have to use one of the others, I am extremely sensitive to chlorine now.