Quick to install, the PF40 Kit consists of an upper grille which is fitted into the IQAir system’s base. Use the 8 screws to secure it to the bottom of the base. A synthetic coarse dust filter pad is held in place by a lower grille that is secured by four clips. The filter pad has a rough, cottony side and a smooth side. Place the filter on top of the filter grille with the rough, cottony side facing outward. When properly installed the rough, cottony side will be facing the floor when the system is in its upright position.