CPR is a means of providing breathing and circulation to an unresponsive person. It is best taught in a training class. In general, the steps of CPR can be remembered as ABC:
Airway: place the victim flat on his back on a hard surface and open his airway by tilting the head back with one hand while lifting up the chin with your other hand.
Breathing: look, listen and feel for signs of breathing. If the victim is not breathing normally, give two slow rescue breaths.
Circulation: Check for signs of response to the rescue breaths (such as normal breathing, coughing or movement). If the victim is responding but not breathing normally, continue giving rescue breaths (one breath every five seconds). If there are no signs of circulation, begin chest compressions by placing the heel of one hand on the lower part of the victim's sternum and then placing the other hand on top of the first hand. Depress the sternum 1.5 to 2 inches and perform 15 compressions to every two breaths. If the victim responds, stop the compressions. If the victim begins breathing normally, turn him onto his side and wait for rescue personnel.