Imam Jafar al Sadiq (as) was asked about Ghusl e Janabat.
So, Imam (as) said : Begin with your two palms, then wash your private part. Then pour water upon your head three times, then pour the water upon the rest of your body, twice.
So whatever the water flows upon, so it has been purified.
Women should not keep their hair down while doing Ghusl e Janabat
Imam Abu Abdillah (as) said : A woman should not let down her hair when she is doing Ghusl e Janabat.
Divine Treasure 