If you have an accident, you should first of all, ensure your car is secure, then report the accident to the police. You should then call your insurer and report the accident. If you can’t contact your insurer, you should do what you can to prevent further loss or damage to your car, and this may include having it towed. You should then contact your insurer as soon as possible.
If your accident involves another driver and car, then you should also be exchanging contact and insurance details with the other driver.