Dirga Pranayama is also known as the three part breath because in this type of pranayam we are actively breathing into three parts of our abdomen.
In this type of Pranayam, the breath is continuous, inhaled and exhaled with the help of nose. The inhalation starts in the first position, the low belly; then moves to the second position, the low chest; then to the third position, the low throat. The exhalation starts in the low throat, moves to the low chest, and finishes in the low belly. Place your hands on the individual positions to feel the breath rising and falling through each position. When you start practicing, you may want to individually isolate the movement in each position, using the hands. When you start enjoying with inhalation and exhalation then start practice without the hands. Eventually relax the effort of the Pranayama and breathe into the three positions gently, feeling a wave of breath move up and down the torso.