WARNING: This page is about a different car, the 2008 Chevrolet Malibu Classic. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: View Of Lamp Bulb From Dome Lamp Mounting Bracket
Courtesy of GENERAL MOTORS CORP.
Install the dome lamp bulb into the dome lamp mounting bracket.
Install the lamp bulb lens to the dome lamp assembly.