Pranamaya breathing to calm the mind

In yoga we use alternate breathing "alternate nostrils" to balance the two hemispheres of the brain and the sympathetic and parasympathetic systems.

Take an inhale through the left nostril, blocking the right nostril with your thumb. Release the right nostril and exhale to the right.

Then take an inhale with the right nostril blocking the left nostril, then exhale through the left nostril. Continue as long as necessary until you get a calm mind.