Negotiation is usually done with the liable party’s insurance company present. Depending on how the insurance company perceives your case, they could agree to pay you some benefits, quickly. If they refuse, you will have to negotiate, and file a demand, providing proof (medical records and bills) of why you deserve that much.
If negotiations are unsuccessful, your case may go into mediation where a third party joins the dialogue to try to resolve the issues. The two sides present their arguments to a neutral party, and this party ensures both sides are heard. Mediation ends when the two parties have come to an agreement.