This is a very common and simple meditation technique. Sit down comfortably, while keeping your back straight. Don’t move around, it could release the energy. Take a deep breath. Keep the air for 2-3 seconds, then slowly exhale. Continue breathing until you feel very relaxed. It can usually take 3-5 minutes. You can also use sound for the concentration : You can listen to a bell according to the rhythm of your breath or include quiet music.