Dell Dimension 4100 - Manual (Page 59)

Adding Parts 59
8 Slide the new drive into the bay, and secure the drive with the three
screws.
9 With the slots on the drive cage extending slightly beyond the front of
the computer, lower the drive cage and slide it toward the back of the
computer until the cage locks into place.
insert
tabs (2)
screws (3)
slots (6)