The Messenger of Allah ﷺ said to them regarding the washing of his daughter, "Begin with her right side and the parts washed in ablution."
حدثنا إسماعيل عن خالد عن حفصة
أن رسول الله ﷺ قال لهم في غسل ابنته ابدأن بميامنها ومواضع الوضوء منها
Its isnad is sahih. It has occurred many times before, and it is in the Sahihs. See 2074, 17173, and 17180.