Supplies you will need; paper, paint, something to spread the paint on, and of course lots of dinosaurs. I would suggest cheap ones since you are dipping them in paint. We use acrylic paint for all of our arts and crafts, the boys couldn't understand why I wouldn't let them dunk the Imaginext dinos in there;-)
After they finished walking their various dinosaurs across the paper they had lots of tracks. Once the paint dried we spent lots of time inspecting the footprints and trying to match them to the correct dinosaur.