1) Open their airway by placing one hand on the forehead and gently tilting their head back and lifting the chin. Remove any visible obstructions from the mouth or nose.
2) Pinch their nose. Seal your mouth over their mouth and blow steadily and firmly into their mouth, checking that their chest rises. Give five initial rescue breaths.
3) Place your hands on the centre of their chest and, with the heel of your hand, press down by one-third of the depth of the chest using one or two hands.
4) After every 30 chest compressions at a steady rate (slightly faster than one compression a second), give two breaths.
5) Continue with cycles of 30 chest compressions and two rescue breaths until they begin to recover or emergency help arrives.