Thank you so much for doing that!
Only problem is that the first 1:30 of that video were blurry, so I couldn't see EXACTLY what you did.
I get the concept of skewing the shape so I can make 90 degree angles, but what tool were you using to draw the lines? When I use the Pen tool it blocks off parts of it in white.
Also, what kind of layers do you have? Did you duplicate the first layer w/ the image on it, and then create a new layer on top of those