If a child collapses, immediately ensure the area is safe before approaching. Check the child's responsiveness by gently shaking and asking if they are okay. If unresponsive, call for emergency help right away. Open and check the airway, and if the child is not breathing normally, begin CPR starting with 30 chest compressions followed by 2 rescue breaths. Continue CPR until the child starts breathing or professional help arrives. If possible, use an AED as soon as it is available. If the child is breathing normally but unconscious, place them in the recovery position and monitor their condition until help arrives.