Whenever the Prophet ﷺ took a bath after Janaba he started by washing his hands and then performed ablution like that for the prayer. After that he would put his fingers in water and move the roots of his hair with them, and then pour three handfuls of water over his head and then pour water all over his body. (Using translation from Bukhārī 248)  

أَنَّ النَّبِيَّ ﷺ كَانَ إِذَا اغْتَسَلَ مِنَ الْجَنَابَةِ «بَدَأَ فَغَسَلَ يَدَيْهِ ثُمَّ تَوَضَّأَ كَمَا يَتَوَضَّأُ لِلصَّلَاةِ ثُمَّ يُدْخِلُ أَصَابِعَهُ الْمَاءَ فَيُخَلِّلُ بِهَا أُصُولَ شَعْرِهِ ثُمَّ يَصُبُّ عَلَى رَأْسِهِ ثَلَاثَ غُرَفٍ ثُمَّ يُفِيضُ الْمَاءَ عَلَى جِلْدِهِ كُلِّهِ»  

Jumay' ibn Umayr, one of the sons of Banu Taym Allah ibn Tha'labah, said: Accompanied by my mother and aunt I entered upon Aisha. One of them asked her: How did you do while taking a bath? Aisha replied: The Messenger of Allah ﷺ performed ablution (in the beginning) as he did for prayer. He then poured (water) upon his head three times. But we poured water upon our heads five times due to plaits. (Using translation from Abū Dāʾūd 241)  

دَخَلْتُ مَعَ أُمِّي وَخَالَتِي عَلَى عَائِشَةَ فَسَأَلَتْهَا إِحْدَاهُمَا كَيْفَ كُنْتُمْ تَصْنَعُونَ فِي الْغُسْلِ؟ فَقَالَتْ عَائِشَةُ «كَانَ رَسُولُ اللهِ ﷺ يَتَوَضَّأُ وَضُوءَهُ لِلصَّلَاةِ ثُمَّ يُفِيضُ عَلَى رَأْسِهِ ثَلَاثَ مَرَّاتٍ وَنَحْنُ نُفِيضُ عَلَى رُؤُوسِنَا خَمْسًا مِنْ أَجْلِ الضُّفُرِ»  

"They argued about Ghusl in the presence of the messenger of Allah ﷺ. One of the people said: 'I perform Ghusl in such-and-such a manner.' The Messenger of Allah ﷺ said: 'As for me, I pour three handfuls of water over my head.'" (Using translation from Nasāʾī 250)  

تَمَارُوا فِي الْغُسْلِ عِنْدَ رَسُولِ اللهِ ﷺ فَقَالَ بَعْضُ الْقَوْمِ إِنِّي لَأَغْتَسِلُ كَذَا وَكَذَا فَقَالَ رَسُولُ اللهِ ﷺ «أَمَّا أَنَا فَإِنِّي أُفِيضُ عَلَى رَأْسِي ثَلَاثَ أَكُفٍّ»