Nextar X3-02 Owner's Manual page 15

Calibrate
Tap in the settings menu to calibrate, the screen will display as below:
This item is used to calibrate the sensitivity of the touch screen. Tap the center of "+" as it
moves around the screen. If you touch the center of "+" every time, it will disappear after
having moved through a cycle (center→top left→bottom left→bottom right→top right).
Tap the screen to return to the settings menu.
Note: If "+" doesn't disappear, you should calibrate again.
Volume
Tap in the settings menu to enter Volume settings menu for volume adjusting, as
shown below:
Tap the buttons to adjust the volume. Then tap
General Setup
to confirm or tap
15
to cancel.