DDR "conceptually" is a very simple game. There's a platform with four arrows: up, Down, Left and right.

About DDR

DDR Platform

There are Four stationary arrows at the top of the screen and arrows scroll up from the bottom of the screen over the stationary ones.

DDR Screen

When the scrolling arrows overlap the stationary arrows, you then hit the corresponding arrow on the platform. thats basically it. But ur going to have to work on your coordination first