Remove the 4 screws on the bottom of the enclosure and remove the outer shell
Set one drive to Master and the other drive to Slave with the appropriate jumpers on the hard drive itself
Installing the inner drive:

connect the IDE cable and power cable
place the drive inside the Concord against the back panel

install the 4 mounting screws to hold the drive in place
installing the outer drive

connect the IDE cable and power cable

install the 2 screws on top and 2 screws on the bottom to secure the drive
replace the outer shell and install the 4 rubber feet/screws
you are finished!