Complex sentence: Tate was left alone with Eunick, who was being babysat by Tate's mother, Kathleen Grossett-Tate, while the children where upstairs playing around, Tate's mother called up to them to be quiet.
Split into simpler sentences: Tate was left alone with Eunick, who was being babysat by Tate's mother, Kathleen Grossett-Tate. While the children were upstairs playing, Tate's mother called up to them to be quiet.