Calibrate touch screen

    1
    Tap the button Calibrate touch screen.
    Configure Machine ->  System Settings ->  Display ->  Calibrate touch screen
    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 Calibrate the Touch Screen - With the Help of a Keyboard).