It turned out to be fairly easy to model the hands, simply involved making extrusions in a polygon cube with 4 subdivisions and with the 'Keep Polygon Faces Together' option turned off.
The tutorial also showed me how to make fingernails, which I managed to do by cutting and extruding faces in the fingers.
I was so pleased with myself that I also decided to put some nails in the gorilla's toes as well, using the same method.
The next step is to model Cornelius' head and face; this is the part which I am most anxious about because I have already made several unsuccessful attempts at modelling a face. I hope that I can get this done by tomorrow, because if I don't, I will officially be behind schedule.