A few simple actions can save a life before you reach a hospital.
For a bleed: press hard on the wound with a clean cloth and keep pressing. Raise the part if you can.
For a burn: cool it with clean running water for many minutes. Do not put oil, toothpaste or ice.
For choking in an adult: give firm blows between the shoulder blades. For a baby, hold face-down and support the head.
Keep emergency numbers and the nearest hospital saved. Do not treat serious cases at home.