What is it?
Ghusl is an Arabic term referring to the full-body ritual purification.
When and why to perform it?
It is mandatory to perform before the performance of various rituals and prayers, for any mature Muslim after having sexual intercourse, ejaculation, or completion of the menstrual cycle.
How to perform it?
Step 1 - Form the intention in the heart to purify oneself from major impurity: janaabah (impurity following sexual discharge), menses or nifaas (postpartum bleeding).
Step 2 - Then say Bismillah and wash the hands three times, then wash any dirt from the private part.
Step 3 - Then do wudoo’ as for prayer, a complete wudoo’.
Step 4 - Then pour water over the head three times, and rub the hair so that the water reaches the roots of the hair.
Step 5 - Then wash the body, making sure that the water reaches all parts, starting with the right side of the body and then the left, and rubbing it with the hands so that the water reaches the entire body.
The evidence of this method from Hadith:
It was narrated that ‘Aa’ishah (may Allaah be pleased with her) said: When the Messenger of Allah (blessings and peace of Allaah be upon him) did ghusl for janaabah, he would wash his hands and do wudoo’ as for prayer, then he would wash himself, then he would run his fingers through his hair, then when he thought that it [the water] had reached his skin, he would pour water over it [the head] three times, then he would wash the rest of his body.
Narrated by al-Bukhaari (248) and Muslim (316).
Learn and follow this method my brothers and sisters in Islam. It is really important as purity is a part of Islam.