The Cha Cha is done to a two, three, four and one count, and it consists of multiple rock steps and chasses. A rock step is a step in which all the weight is placed on the front foot and then transferred to the back foot without ever picking up the back foot, while a chasse is a sideways step in which the feet are brought together before taking another step so that the back foot is always catching up.
To start the Cha Cha as the leader, take a rock step forward with the left foot on the two beat of the music, and then rock back on the three beat. Next, chasse to the left with a small step on the four beat, and then bring the right foot together with the left foot on the half beat. On the one beat, take step to the left, and then rock step backwards with the right foot on the two beat. Rock back on the three beat, and then chasse to the right twice on the four and one beats.
From this point on, the dance is repeated with rock step and chasses to the left. To complete the dance as the follower, reverse the steps so that the dance begins with a rock step backwards on the left foot.