The lower tray of VitalSleep can be adjusted forward to advance your lower jaw. This will prevent the tongue and soft tissue of the throat from collapsing the airway. As a result the diameter of your airway will increase and the turbulent sound of snoring will be reduced.
Turning a screw clockwise will bring the lower tray forward.
Each screw should be turned equally to not skew the device.
To help the screws engage it may be necessary to squeeze the top and bottom trays together as shown in the image below.