Seat the cable on the keyboard into the connector on the system.
Hold the keyboard at a 15 degree angle.
Insure the tabs on the back edge of the keyboard go under the frame of the system.
Rotate the keyboard down and apply pressure to the Y key to seat the connector.
Apply pressure to the Fn and Right-Arrow keys to ensure the front tabs of the keyboard are fully seated. You should hear the front tabs snap into place.
Close the LCD cover.
Turn the machine over.
Secure the keyboard with these four screws on the ThinkPad X20 and X21 systems. There are only three screws on the ThinkPad X22, X23, and X24 systems to install. A diamond-shaped icon identifies the screws.