Place each pattern over a piece of cardboard or a manila folder, and cut the pattern out using an X-Acto knife. (You should end up with identical copies of the pattern on paper and on cardboard, one for each child).
At the Party:
Have the children decorate the paper cut-outs with crayons or markers.
Once they are decorated, glue the paper patterns to the cardboard patterns.
Fold each piece along the dotted lines.
Fold the tabs inward, and tape them and the edges closed.
Tape the upper portion of the truck (the Dump Truck Top) to the body at an angle.