There’s no set number of planes and you don’t have to draw them. It’s more of an idea to help you process the complex image into something more simple - by simplifying the pear into planes in your mind, you can think about how much light each plane is receiving from the light source or bounce light, which gives you information on how dark or light your value shapes will be. You have the right idea here. Try taking away the dark outlines and shade your shapes evenly, using the edge of the shape as the separation between values.