Musannaf Ibn Abi Shayba 1:686

Husayn ibn Ali narrated to us, from Za'idah, from 'Ata' ibn al-Sa'ib, who said: Abu Salamah ibn 'Abd al-Rahman narrated to us, saying: 'A'ishah narrated to me that when the Messenger of Allah (may Allah bless him and grant him peace) would perform ghusl from janabah, the vessel would be placed for him. He would pour over his hands before inserting them into the vessel. Once he had washed his hands, he would insert his right hand into the vessel, then pour with his right hand and wash his private part with his left. When he finished, he would pour with his right hand onto his left and wash them both. Then he would rinse his mouth and nose three times. Then he would pour over his head the fill of his two palms three times, then he would wash the rest of his body.