If you can draw the letter "S" and a Question mark, then you will be able to follow along on this video. It will take a little more practice to get the horse's eyes and hose and ears horse-like, and the unicorn horn is the extra step!
Hopefully this video is more fun than most tutorials, and you will be able to remember the steps when you are talking on the phone, doodling. Or when you have a sharpie marker in your hand and want to talk someone into getting a fake unicorn tattoo. Whatever.