Here’s the basic procedure for diaphragmatic breathing:

1. Sit in a comfortable position or lie flat on the floor, your bed, or another comfortable, flat surface.
2. Relax your shoulders.
3. Put a hand on your chest and a hand on your stomach.
4. Inhale through the nose with a small, controlled breaths (don’t move nose hairs!)
5. Expand diaphragm (remember, you want oxygen getting to the further lower parts of your lungs, to the alveoli)
6. Stay out of the traps/neck. If you feel like you’re raising your shoulders or tightening your neck, lightly drop your shoulders and focus attention on breathing through lower ribs and diaphragm.
7. Exhale through the mouth
8. Soften through sternum to get a full exhale

Don’t overthink this!  Don’t worry about counting the seconds you inhale/exhale. Breathe comfortably.