Complex sentence: She spends the day frantically trying to conceal David's body from Lucy, nanny Carla and neighbor Madeleine before finally buying a panda costume off of a man who comes to sing Lucy a birthday song and hiding the body in the costume.
Split into simpler sentences: She spends the day frantically trying to conceal David's body from Lucy, nanny Carla, and neighbor Madeleine. She finally buys a panda costume off of a man who comes to sing Lucy a birthday song, and hides the body in the costume.