Complex sentence: When Jane finds the treasure and Peter and the Lost Boys make her the very first Lost Girl, she has a change of heart and throws Hook's whistle away, but Tootles finds it and, not realizing what it is for, blows it.
Split into simpler sentences: When Jane finds the treasure, Peter and the Lost Boys make her the very first Lost Girl. She has a change of heart and throws Hook's whistle away, but Tootles finds it and, not realizing what it is for, blows it.