THE ULTIMATE KNEE DROP GUIDE
An official mr. Boogie product
Step 1. Place your left foot behind your knee and make sure your toes are further then your knee, so you don't hurt your knee.
Step 2. Drop on you toes.
If you like, you can also do it with right foot behing left knee of course.
Here's the vid:
Click here to watch KneeDropGuide
Damn this move is so easy

But well, if you don't know what to do I can understand your question.