IBM Aptiva Reference Manual page 110

106
2 Remove the metal bay cover.
.
3 From the back of the drive bay, carefully insert a
3.5-inch disk drive then secure it with four screws on
the sides.
4 Re-install the drive bay into the housing as in the
following figure:
a Align the drive bay with the notch.
b Pivot the drive bay toward the housing until
the tab clicks into place.
Adding and removing drives