Epson EL 486UC - Manual (Page 82)

4. Align the hard disk drive so that the cables lead toward the
diskette drive bays and the four holes at the base of the
drive are above the four pegs, as shown below.
5. Gently lower the drive over the pegs. When the hard disk
drive is resting on the pegs, it will not move from side to
side.
6. Lower the mounting bracket over the hard disk drive,
making sure that the slots in the mounting bracket fit over
the tabs on the base of the computer.
Installing and Removing Drives 4-9