Start in the nape area, taking diagonal partings and take subsections that are vertical, bringing them out to 90 degrees, the hair should be 4 inches in leangth or more at the nape. Each subsection will have 3 vertical parting.
Then continue to do this until you get to the back crown.
Switch to horizontal partings and again take vertical subsections bringing them out at 90 degrees and cutting.Each subsection will have 3 vertical sections.
At the top make sure you leave the hair 3 to 4 inches long, over directing the front hairline back to the top of the head to ensure length is kept.