WARNING: This page is about a different car, the 2004 Pontiac Sunfire and 2004 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
Connect the electrical connector.
Install the switch to the IP carrier.
Press the switch until the retaining tabs are fully engaged.
Fig 1: Installing Rear Compartment Lid Switch Retaining Tabs