Figure 6-9: Screwing The 3.5" Disk Drives - Datatech Enterprises Apex 386SX/20 User Manual

Figure 6-9: Screwing the 3.5" Disk Drives

Connect the power cable and the hard disk controller cables. Note that
there is only one possible way to connect the power cable and hard
disk cables owing to the shape of the connectors, so it is impossible to
make a mistake.
The two hard disk controller cables are of different sizes: the red wires
on the cables should be connected so that they are toward the central
portion of the case.
Removal
To remove a 3.5" disk drive, reverse the procedure described above.
Disconnect the cables, undo the mounting screws, slide the drive out
and remove the mounting guides.
8 Chapter 6: Appendix