Step 3: Sculpting
Make a little ball of Sculpey and squish it into a circle. Use it to decorate Robin's belt buckle.
For Batman's ears roll two Sculpey balls and shape them into pointy cones. Use your thumb to smoosh them into place on the side of the gnome's head. They'll probably stick there in place and hold on their own.
You should have excess Sculpey rolled out. You can use a razor knife to cut out a Bat-a-rang. Make a paper template if needed.