WARNING: This page is about a different car, the 2005 Pontiac Pursuit and 2005 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: View Of Shift Control Knob & Boot
Courtesy of GENERAL MOTORS CORP.
Install the shift control knob (1) to the shift control assembly.
Install the shift control boot collar (2) to the shift control knob (1) and twist 1/4 turn to lock.