All you really need is clay of many colors, although the main color is gray.
I don't have many pics of the process But they are pretty self-explanatory. Its mostly making small cylinders of the body color and then adding the details.
Don't worry too much about detail, as long as the main parts are there, it will look fine.
take a break if those little bits of clay get tedious
slow and steady wins the race!
look at lots of pictures of different angles
I hope this instructable helps and please post pics of your own in the comments below. Thanks!