PID parameter recommendations and approach

[sharkwsk]

Hi, I am trying to use my AC unit to control temperature to one of the rooms at my home. Below is sample climate configuration for the PID thermostat. The room i am trying to heat is comparably small and heats up quickly

climate:
  - platform: smart_thermostat
    name: Smart Thermostat Bed1
    unique_id: smart_thermostat_bed1
    heater: climate.ac_192_168_100_100
    target_sensor: sensor.multi_sensor_1
    min_temp: 10
    max_temp: 35
    ac_mode: false
    target_temp: 24
    away_temp: 14
    keep_alive:
      seconds: 60
    kp: 5
    ki: 0.01
    kd: 500
    pwm: 00:15:00
    debug: true

I need some guidance on how I can approach fine tuning of the PID values,

I am trying to test the thermostat by - changing the target temp to a higher value to switch on the AC heater. But when I lower the dial to lower temps, I do see the PID output changes to 0. But the AC heater never turns OFF. Due to this I do see large overshoot and I am not sure how I can fine tune it step by step. I don't even know if that is a correct way to test the PID thermostat