Complex sentence: The first part examines the behaviour of the horse while it is being harnessed and loaded, then unloaded and unharnessed, and the remaining three parts evaluate the way the horse behaves when being driven.
Split into simpler sentences: The first part examines the behaviour of the horse while it is being harnessed and loaded, then unloaded and unharnessed. The remaining three parts evaluate the way the horse behaves when being driven.