Pontiac 2005 Bonneville Owner's Manual page 208

Once you have loaded the CDs in the magazine, slide
open the door of the CD changer. Push the magazine
into the changer in the direction of the arrow marked on
top of the magazine.
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Close the door by sliding it all the way to the right.
When the door is closed, the changer will begin
checking for CDs in the magazine. This will continue for
up to one and a half minutes depending on the
number of CDs loaded.
To eject the magazine from the player, slide the CD
changer door all the way open. The magazine will
automatically eject. Remember to keep the door closed
whenever possible to keep dirt and dust from getting
inside the changer.