Start by sorting out the thumbtacks if you'd like. Doing it by color will be really fun for preschoolers (just make sur they're carefully wth the sharp end!)
Show you child how to put the thumbtacks into the ball. You can give them a little direction or just let them go for it like I did
If doesn't have to be completely full to be done, just whenever your child has had enough. That's why the smaller balls are better than larger.
To hang, stic the shorter end of the ornament hook into the styrofoam and push it all the way inside
Push it down, including the top hook until there's just a small hook left on top.
Then tie a piece of thin string, like this bakers twine, through the hook and make a knot with both ends. Hang on your tree and enjoy!