How to perform CPR
The victim should lie on a flat, hard surface. The place should not be crowded.
Follow the Chain of survival
One thing to remember is, assuming that you are alone, when you find someone down, first establish if they really need CPR: are they breathing? do you see any signs of movement?
Remember to look, listen and feel, for any signs of movement, for breath sounds and for air movement by placing your ear over their mouth.