I found my Clarion VRX8370R in the Camper I bought and I wasn't able for month to understand it.
The Owner Manual was perfect and just what I was searching for.
Text excerpt from page 11 (click to view)
Lock the feet in position by fully tightening up the locknuts.
The appliance must be level and resting on all four feet. It must not tilt when pressure is exerted on one side only. If necessary, use a spirit level to check that it is perfectly level. The floor must be clean, dry and free of any wax residue or other polish to prevent any risk of sliding. Never use viscous substances to move the appliance by sliding it across the floor! It is inadvisable to stand the appliance on long pile carpet or rugs or on layers of foam rubber, as this could make it unstable. Place a rubber mat beneath the appliance if the floor is made of very small tiles. If the appliance is to be placed on non-solid flooring, especially made of wooden joists and flexible boards, a waterproof wood panel, 15 mm thick, must be secured with screws to at least two of the floor joists. If possible, the machine should be placed in a corner of the room, as this is where the joists are most firmly fixed and have less tendency to flex. Never use wedges of wood, cardboard or other similar materials to compensate for unevenness in the floor. If space is tight and you cannot avoid placing the machine next to a gas oven or coal burning stove, a sheet of insulating material (85 x 57 cm), covered with aluminium foil on the side facing the oven or stove, must be fitted between the two appliances.