Basically Hata (or Hatha) yoga uses the Prana part of the ’human body’ whereas Raja yoga uses the mind (maanas).
Prana can be treated as the sum total power in the human body. It is related to mind and also to the universal power/energy.
Prana in the body assumes five forms called Vaayus. These Vaayus will be working in different parts of the body and it is not possible to identify them exactly at a given time. Out of the five Vaayus, Mukhyaprana is the main one. Mukhyaprana resides in lungs and related to breath. So the Hatha yogi controls the Prana through breath control.
In general the Hatha yoga practice steps are as follows:
Asanas – To control the physical body (muscles) and keep healthy.
Kriyas – Purify the internal organs ( Nauli, Dhouti, Neti etc.)
Pranayama – Control of breath
Bandhas – To fix the prana in different parts of the body (Jalandhara, Udyana etc.)
Mudras – Combine Bandhas, pranayama and asana in a particular way to control the prana and attach it to mind. (Maha mudra, Maha Bandha etc.)
Prana-laya stages (or Nada-nu-sandhana) – Merging the prana with mind or keeping prana at a particular spot in the body. When mind passes through that sport, prana and mind will merge (laya state) which will leads to self-realisation.
Hatha yogi can exhibit many supernatural powers, like floating in air (levitation), floating in water, stopping his heart etc. Some of the Hatha yoga practices are very difficult and time consuming. Always there will be a danger that the Hatha yogi may develop passion towards super natural powers and public shows rather than progress towards self-realisation.