Instructions
Place the "Wii Fit" game disc in the console. Point your Wii remote at the game's icon and press the "A" button to launch it. Select "Start" and press the "A" button.
Point at the "Settings" button, indicated by a wrench icon in the top-right edge of the Wii Fit Plaza, and press the "A" button.
Point at the "Install Channel" button and press the "A" button.
Press the "OK" button to add the Wii Fit Channel to your Wii console's main menu.
Press "OK" again to save the channel to the system memory of your Wii.
Press the "OK" button a third time to return to "Wii Fit."