Turn the centre knob to the right (clockwise), and set it to "Auto" or your desired fan speed

Make sure that the light under the A/C on the first knob is on. If there is no light, press on the A/C and the light should turn on, and the wind coming out should be of a cooler temperature

Turn the centre knob to the left (anti-clockwise) and set it to "0" to turn off the car's aircon fully