What to do in an emergency?

Would you know what to do in an emergency?
Last year my boyfriend was in a car crash which resulted in the car being turned upside down in the middle of the road.  Would you know what steps to take as a witness? 
Luckly two men came across the crash and stopped to help, instead of calling an ambulance they cut him out of the car.  He was complaining of neck and back pain and removing him from the car could have resulted in further damage.  Although these men thought they were helping they could have made the situation alot worse.  I intend to make a commerial informing the public of what steps to take in an emergency, in this case a car accident.