for the base of it I used normal craft foam, which you can find in the kids craft section, I found mine in poundland, and I just place one beside each other and used masking tape to hold them. Then I just drew them on with the template I made.
Next I did the paper mache, I also forgot to add more craft foam too make it look 3D at the start, and i did paper mache again over the whole thing.
I painted the whole thing using normal acrylic paint and I'm done I think I might make the dark grey a lighter grey colour. Over all I think it turned out pretty well the only thing I don't like about it is probably the way i painted it meaning I'll probably repaint it.