Calibrate touch screen

    1
    Tap the button 校准触摸屏.
    设置机器 ->  系统设置 ->  显示 ->  校准触摸屏
    2
    The Calibrating Touch Screen window appears.
    2. 3
    Tap the target circles one after another (top left, bottom right, top right).
    4
    Finally tap the Accept button.
  2. The calibration of the touch screen is complete.

If this window does not appear, then a hardware keyboard is to be connected to the USB socket (see 校准触摸屏 - 利用键盘).