Answer:
Call the emergency number (the code)
Step-by-step explanation:
If a person is unresponsive, the first thing you should do is call the emergency line for help. The number depends on where you live - 911 for the US or 999 for the UK.
If you have the knowledge about the first aid, like clearing the airway or CPR, this should be tried only after you call for help - the emergency is the number one resource because they will likely have the technical support to help the person as efficiently as possible.