Watch the club dance sequence from Step Up (the original) on YouTube.com or through the movie several times in a row to gain a familiarity with the steps and movement.
Download or purchase the music from the scene.
Master the steps a few seconds at a time. Watch the first eight counts of the dance, pause the film and imitate the steps. The first few choreographed steps in the sequence are three walks to the side with a pop on the last step. Step the right foot to the right, cross the left foot over and repeat. On the last cross step, throw your shoulders and hips back to accent the pop. Repeat to the left.
Rewind and rehearse the eight counts you just tried in time with the film. If you matched it identically, move onto the next eight counts or few seconds of dancing. In this sequence, it's two small lunges to the side. Bend your right knee slightly and extend the left leg, then step the left leg in, bend it slightly and extend the right leg. Swing and pump the arms to accent each lunge.
Move onto the next sequence. Pivot in place to the back then the front. Step on the right foot and dig the ball of the left foot, then step on the left foot and dig the right. Pump the arms in front of the body to accent the movement. Pivot to face the wall to your right, fanning the arms overhead. Repeat the entire step sequence, starting with the step crosses to the right, facing this wall.