Asta,
Our trainer loaned me a book you might want to find for Gabby, "The New Complete Junior Showmanship Handbook" by Marsha Hall Brown and Bethny Hall Mason, copyright 1980. The text may be geared towards kids slightly older than her, but if she can't appreciate it today she will soon enough in the next few years. It has good pictures and explains things in simple terms. You could probably find an old copy on Amazon or eBay.
Susanne