Start by cutting the top and bottom of the pepper off. This creates a flat surface on the bottom and allows you to see through to the inside.
Make your first cut into the pepper to the right of the pith (the bitter white part).
Your next cut will be right before the next line of pith.
You now have one section of pepper, and a peek at the inside.
Next, you will be cutting behind the pith.
And then once again in front of the pith.