Musannaf Ibn Abi Shayba 1:685

Waki’ narrated to us, from Hisham ibn ‘Urwah, from his father, from ‘Aishah, that the Prophet (may Allah bless him and grant him peace) performed ghusl (full ablution) for janabah (major ritual impurity). He began by washing his palms three times, then he performed wudu (ablution) like his wudu for prayer. Then he inserted his hand and combed the roots of his hair with it until he felt that he had cleansed the skin. Then he poured water over his head three times, then he poured water over the rest of his body.