Complex sentence: Zellaby, whose "son" David is one of the children, is at first eager to work with them, trying to teach them while hoping to learn more about them; the children are placed in a separate building where they will learn and live.
Split into simpler sentences: Zellaby, whose "son" David is one of the children, is at first eager to work with them, trying to teach them while hoping to learn more about them. The children are placed in a separate building where they will learn and live.