Lexmark C920 User Manual page 31

If an option card has been installed, you may have to remove the option card before installing the hard disk.
1
Remove the system board access cover (see Removing the system board access cover).
2
Align and press the ribbon cable connector into the connector on the system board.
3
Flip the hard disk over, and then press the three posts on the mounting plate into the holes on the system board.
The hard disk snaps into place.
Installing and removing options
Installing a hard disk
31