This video describes different ways of doing Ghusl in a simplified form. In Islamic law, Ghusl is the process of washing the body in order to purify it from spiritual impurities in a specific way.
It is necessary to remind that the content of this video is based on the Fatawa (a ruling on a point of Islamic law given by a recognized authority) of the grand Ayatullah al-Sistani; therefore, for further explanation and definition you can refer to other original sources or ask someone authorized to answer.