Instructions
Insert the GameCube game in the Nintendo Wii in the same way you would a Wii game. Make sure the game's labeled side is facing to the right if the console is upright.
Wait for the game to boot and appear in the top of the Wii's home menu. Use your Wiimote to move the cursor to the game, and select it by pressing the "A" button.
Open the top flap on your Wii; there are slots that allow you to plug in a GameCube controller. Plug the GameCube controller into any of the ports.