To use this technique, inhale for four
counts, hold your breath for seven counts, and exhale for eight counts; repeat. Why the weird irregular numbers? Precisely because they’re irregular, you have to concentrate on counting. This distracts the mind while the oxygen relaxes it.
Box breathing is so called because it is done in four stages. Inhale for four counts, hold for four counts, exhale for four counts, hold for four counts; repeat.