If replacing the dome lamp bulb, you should install the dome lamp bulb to the socket. If replacing the reading lamp bulb, you should install the reading lamp bulb to the socket. You also need to install the reflector to the dome lamp, ensuring the retaining tabs are fully seated. Then, please position the lens to the headliner with the horizontal tab facing forward, position the horizontal tab above the headliner and push the lens forward to seat the tab. Finally, you should push upward on the rear portion of the lens, seat the rear lens retaining tab, and pull down on the lens to ensure that the lens is secured to the headliner.