The drive mounted in the hard drive carrier. Note the two torx screws and orientation of carrier. Line the screws up and use the torx wrench to snug them (They don't need to be more than snug.) You should be able to remove the existing hard drive carrier from the back of the drive by pulling from the back of the drive. Be sure ot unplug the power and usb connector and give the drive a few seconds to stop spinning before you pull the sheet metal piece away.