Get out your supplies. This goes for most braiding: do this with damp hair(not soaking). It will make it easier b/c the hair is frizzing, it's relaxed when it's wet (so to speak).
Brush out any tangles, knots, etc.
Section of the crown of your hair and pull to pack of the head. Separate into 3 sections.
Here's what is should look like. Good luck!