The best way to clean your quartz counter-tops is to use a mild household cleaner; like Lysol®. These surfaces are heat and scratch resistant but not indestructible; so make sure to use cutting boards and potholders to protect your beautiful new surfaces.
While these types of surfaces are heat and scratch resistant, they are not heat and scratch proof. You have invested in some amazing, brand new counter-tops, so be sure to protect them with heat pads and cutting boards to ensure their integrity for years to come!