Make sure the person is laying on their back, preferably on a hard surface, such as floor or ground.
Place one wrist in the middle of the sternum between the nipples, place your other hand on top. Press down on the chest at least 5 but not more than 6 cm. Keep a pace of 100-120 presses / min. Press 30 times, hard and fast.
Then switch to the mouth-to-mouth method. First open the airway by lifting the chins tip up with two fingers and bend the unconscious person's head backwards, using one of your hand on the individuals forehead. At the same time, squeeze the nose using your thumb and forefinger.
Then take a regular breath and let your own mouth cover the mouth of the unconscious person. Blow slowly and gently in air until it is visible that the chest is rising. You should always do two breaths in a row.
Switch between giving 30 chest compressions and two breaths with air. Continue like this until medical personnel come to the rescue.
If you find it uncomfortable to give mouth to mouth breathing, you can put a thinner textile piece, such as a handkerchief or a t-shirt, over your mouth. If you cannot give mouth to mouth breathing, it is better to just do chest compressions than to do nothing at all .