CPR is best performed when the victim is lying on their back on a hard flat surface
On an adult with no breathing:
Kneel on the side of the victim;
Place one hand on top of the other over the victim's chest. Your arms should be straight and your shoulders should be directly over your hands.
Press down 1 - 2 inches. Press down and return all the way up. Do not bounce or rock.
Provide 30 chest compressions counting as follows "1, and 2, and 3, and 4, and 5 . . . and 25, 26, 27, 28, 29, 30."
After 30 compressions, provide 2 rescue breaths.
Repeat the sequence of 30 compressions and 2 rescue breathes 5 times, or for about 2 minutes.
Reassess - checking for breathing.
If there still is no breathing continue to provide chest compressions and rescue breathes, reassessing the victim every couple of minutes (as their condition could change).
Continue to provide CPR until either help arrives, the victim recovers, or you physically can't help any more.