A person who is gasping for breath or breathing abnormally and non-responsive requires resuscitation. Therefore, the answer to the next step is to check for normal breathing and decide what action to take. If unsure what normal breathing is, look at other people, if breathing normally inhalation and exhalation will be silent, effortless and without closer inspection, no apparent chest movements will be noticeable.
In the case of the person on the ground, under normal circumstances* check to see whether he is breathing. Place your ear close to their nose and mouth. Look down the line of their body towards their feet.
Look for movement of the chest rising and falling.
Listen for sounds of breathing.
Feel for expelled air on your cheek.
The results from this check will decide what you are going to do next.
*Current rules and guidance whilst there is a global pandemic continuing should be followed. The New Zealand Resuscitation Council offer the following temporary guideline.