Epson Equity 286 PLUS - Manual (Page 155)

Make sure the holes fit over all the pins and then push the
connector onto the pins.
Caution
If you do not correctly align the holes with the pins, you
could severely damage your hard disk drive when you
push in the connector.
4. Pick up the hard disk drive and hold it above the vertical
mounting area so the mounting plate is facing the
subassembly, as shown below.
Notice that there are two tabs facing downward on the
bottom of the mounting plate. These tabs will fit into two
slots in the right side of the subassembly.
B-l6 Installing and Removing Disk Drives