I am making the Wilton carousel cake for my niece's birthday and I thought that the box would have at least some basic instructions on how to decorate the horses but it doesn't. Has anyone made this cake? If so, how did you decorate the plastic pieces? Royal icing? Fondant? Please help!!! Thanks!

On their website, Wilton says to use royal icing to decorate the horses. See this page, for example.
http://www.wilton.com/idea/Princess-Merry-Go-Round-Cake

I had the same issue, I was dissapointed with this product.

Thank you, Diane! I was searching for carousel cake and though the photo showed up there were no instructions. I never thought to look for Merry-Go-Round cake. Thanks a bunch!