There are four Preset slots on QuNexus. To select different presets tap the Shift / Preset button on the left side of the QuNexus.
The LEDs on the keyboard will swipe to indicate that you are in Preset Select Mode. Then one of the four lettered buttons will light up to indicate which Preset is currently selected (A, B, C, or D). Next tap one of the four buttons to choose a different Preset. Upon making a selection the LEDs on the keyboard will swipe again to indicate that you are leaving Preset Select Mode and entering the chosen preset.