Epson 3865X Plus User Manual page 220

Pull the panel away from the front of the computer.
If you are going to install a hard disk drive in the lower
horizontal position, set the front panel aside and go to
step 4.
If you are installing a diskette drive, remove the slot cover
from the front panel, as described in step 3.
3. Place the front panel face down on a flat surface and use a
screwdriver to remove the screws securing the slot cover to
the panel. Lift out the slot cover, as shown below.
Set the front panel, slot cover, and screws aside.
slot cover
Installing and Removing Disk Drives
B-29