Look at the finished horse at the end of the page (print it off if you can)

Use your HB to lightly draw in the lines(he draws heavily because he is confident of his lines), then use your 2 B and 6 B for the shading

In your drawing pad, draw a rectangle 'frame of reference'(or use the whole A4 page) and shade your paper first to a nice mid value (maybe a 3 or 4 out of 7 on this scale here), smooth it all over with a paper towel. 

Then draw the basic outline, giving all of your attention to the relative proportions of the different sections of the neck and head. Once you are happy that your horse headline drawing doesn't look too short, too long or too fat, go ahead with the next stages of adding darker details and erasing the lighter highlights. This is where your battery-operated eraser gets to be great fun!! (he used white pastel on toned paper for his highlights, you will be erasing highlights).

Take the time on another page to do some practice on the eyes before doing the details on your actual drawing.