The table below gives an outline of the lesson plans available in the "Teachers" section, although there re other resources under "kids" to learn about different composers (in alphabetical sections) and various games for different purposes.  It is an American site so beware issues with notation.  The approach takes inspiration from Orff, Kodaly and Dalcroze pedagogies and there is much to like.  Logo link takes you there.

NB AS AT 29.03.2023 THE CLASSICS FOR KIDS WEBSITE IS UNDERGOING UPDATING AND PERIODICALLY OFFLINE.  MORE NEW RESOURCES ARE PROMISED.