Sunan An-Nasai, Chapter: The Book of Purification

"I asked Aisha about how the Messenger of Allah (saw) performed Ghusl from Janabah. She said: 'The Messenger of Allah (saw) used to pour water onto his hands three times, then he would wash his private part, then he would wash his hands, then rinse his mouth and nose, then pour water onto his head three times, then pour water over the rest of his body.'" (Hasan)