Assignment:
Block in your Dark, Mid and Light values. The notanized image flattens and simplifies the light and shade, that may be helpful to get you started. Once the blockin is done then you can go in and add the variations and work with edges to make the form 3d.
Give your self enough time to finish this off, approx 3-4hrs would be a good guide to aim for.

Demo
Charcoal Pencil on Toned Paper
11x14