At the crash scene, ensure to:
Keep calm and stay in the car as long as it’s safe.
Ensure hazard lights work and are on.
Underestimate no injuries, ensure to call 911.
Ensure you and your passengers get medical attention.
Ensure to stay at the scene till it is safe to leave.
Acquire the credentials of all the involved parties
Note down vital credentials of the police who are present on site.
Shoot photos of the vehicle and all other relevant things at the scene.
Never admit fault only talk to the police and your insurance company. It is not your obligation to give information to anyone that’s not your insurer or lawyer.