Nextar Q4 User Guide - Page 15

General Setup Screen Tap in the settings menu, 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 corner→bottom left corner→bottom right corner→top right corner). 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 cancel. buttons to adjust the volume. Then tap to confirm or tap to 15