You don't need to do anything at this point.  Your insurance company will try to negotiate with the opposing party to attempt to settle the case for significantly less than the amount in the demand letter.  If the case is settled, that will end the matter. If the case is not settled, a lawsuit for negligence will be filed against you, and your insurance company will provide you with an attorney at no cost to represent you.  Don't worry about that because most of these cases are settled without a lawsuit being filed.