Whenever the Messenger of Allah ﷺ wanted to perform the ritual bath after sexual impurity, he would begin by washing his hands before placing them into the vessel. Then he would wash his private parts and perform ablution as he did for prayer. Then he would let his hair drink in the water, and then pour three handfuls of water over his head.
حدثنا ابن أبي عمر حدثنا سفيان بن عيينة عن هشام بن عروة عن أبيه
كان رسول الله ﷺ إذا أراد أن يغتسل من الجنابة بدأ فغسل يديه قبل أن يدخلهما الإناء ثم غسل فرجه ويتوضأ وضوءه للصلاة ثم يشرب شعره الماء ثم يحثي على رأسه ثلاث حثيات
No references are available.
Agreed upon [by Bukhari and Muslim]. Bukhari narrated it in the Book of Ghusl, Chapter on Performing Wudu Before Ghusl, no. 248, and Muslim narrated it in the Book of Menstruation, Chapter on the Description of Ghusl from Janaba, no. 316, from the hadith of Hisham, with this wording.