In step (reading):1， with a detergent (or detergent) to clean and dry the window glass (especially the glass surface oil must be removed， otherwise the impact and lasting effect)2， squeeze both ends of the handle， I heard "bang" was heard， from top to bottom quickly after opening a uniform layer of varnish painted the entire windshield.3， and finally with a towel or paper towel to clean the varnish， this step must be to operate， after the completion of water repellent effect immediate.The product does not cause any harm to automotive glass， please do not worry.