Set Up the Dance Mat
Most dance mats have three or four foam pieces which make up the body of the mat, and a vinyl shell, which is connected to a black box with a cable. For most mats, the foam pieces act like puzzle pieces, sliding together easily to make a larger flat surface. Slip the shell around this foam mat, and zip or snap it closed.
Set the mat at least 3 feet from the TV screen, with the processor facing the TV, and attach the cables to the Wii console. These cables connect to the GameCube controller ports on the Wii itself. They are located on the top panel if you have the Wii set up sideways, or the side panel nearest the power button. Flip the panel up on its hinge to reveal a set of round controller ports. Repeat this process for any other dance mats you're setting up; the Wii can take up to four.
Starting the Game
Insert the game disc into the Wii console, and connect the nunchuk attachment to the Wii remote. Start the game from the Wii menu. Choose one of the game modes, then pick a character. The characters in the game do little to affect your game play, so pick the dancer you like the most. Find a song to dance to, and set the difficulty level accordingly. If you're new to DDR and dancing games, you should choose a slower song, then choose the lowest difficulty setting. When ready, begin the round.
Starting to Dance
The heads-up display for the game has a score counter at the bottom, and a row of four directional arrows at the top. The background shows your character and the visualizer display. The on-screen directional arrows correspond to the four directional areas on the pads. As the music plays, arrows flood toward the top of the screen, across the upper bar. To score points, step on the corresponding area of the pad when an arrow crosses it. When the "Right" arrow hits the screen's "Right" arrow, step on the pad area pointing to the right, and so on. You just need to hit the area, but can leave your foot if you choose--except with stretched-out arrows, which require that you step in time and stay planted. Sometimes you may even see two arrows at the same time, which will require that you jump to hit both.
In the Wii version, motion controls also appear on the right and left arrows as a hand with a Wiimote. When you see those, raise your corresponding arm upward. Don't worry if you miss a few steps, but learn to feel the rhythm so you don't miss too many, otherwise you may lose the round.