Watch the original Wall to Wall video featuring Chris Brown. Along with learning the valuable lesson that's it's probably best not to pick up your car in an empty parking lot late at night, you will be able to observe the Wall to Wall dance as its being danced by Chris Brown and his crew.
Play the video multiple times, pausing and rewinding it so that you can break down the dance moves and copy them yourself.
Search for video tutorials of the Wall to Wall Dance. These tutorials not only break down the dance for you, but the person who is running the tutorial helpfully describes each dance move as well as how to do it. One of the best of these tutorials is by rayray who breaks down the Wall to Wall into multiple parts. She not only breaks down the steps and explains how to perform them, but puts them back together bit by bit so you can see how the entire dance will look when it's put together.
Observe other videos of the Wall to Wall dance as well. You will find plenty of them at YouTube. Since Hip Hop dancing is characterized by improvisation as well as originality, you will be able to take bits and pieces from each video and create your own Wall to Wall dance.
Practice all of the moves you have learned of the Wall to Wall dance and take yourself to the dance floor. You will make an impression, to be sure.