Instructions
Make sure your Xbox 360 is powered off.
Locate the hard drive or drive cover on the console. When the console is on its side, the drive is located on the left. When standing, it is at the top.
Press and hold the release button on the installed hard drive. The hard drive or bay cover (if no hard drive is installed) will loosen and needs to be pulled away from the console.
Slide the rounded end of the new hard drive into position. Press down on the hard drive. A "click" sound will confirm the hard drive is in the correct position.