The control panel is located at the bottom of the touchscreen, as seen in the picture below.

Touch/Press the screen where the fan sign is for fan speed. The aircon will start as soon as you select the desired fan speed.

The 2 knobs below the screen are to adjust the desired temperatures for the aircon - The left knob is for the passenger side and the right for the driver's side (The temperature can be seen of the screen itself).