Using the close up lens focus the camera on ANY subject as long as it is about 6 inches away from the camera.  The close up lenses come in strengths called "diopters" from 1 to 4. The larger the number the stronger the lens.  These are just like reading glasses. You may use one lens or several lenses together to vary your close up distance.   So an For this one photo assignment you still need to follow good composition rules, think creatively and set your exposure correctly.