Sayyidah Aishah (may Allah be pleased with her) says: When the Messenger of Allah (peace and blessings be upon him) took the ritual bath for janabah (major impurity), he would first wash his hands, then perform the ablution of prayer, then put his fingers into the water and run them through the roots of his hair, then take three handfuls of water with his hand and pour them over his head, then pour water over his whole body.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 823