" you have the right to choose any repair Facility "

make sure you and your loved ones are safe against up coming traffic and they can see you, then call authorities ..Take many photos .. call your insurance company or if the other party is at fault call their insurance and make sure they placed a claim .. Get the Claim Number.

Insurance Adjuster can and should get you a Reservation Number for rental car company .. it just makes it way faster and less hassle for you.

They will ask you for some pictures of your vehicle and damages , usually they cant see everything and shop will break it down for them  and write up a supplement.

Usually if your Car is 2 years or older or has more than  30.000 miles on it, insurance company can pay for some used or aftermarket parts .

( Depending on your Insurance policy and insurance company )

Your insurance agent can and will give you plenty of information OR you can call the shop your working with and they can answer lots of your questions .

Some insurance company's will ask for a written Estimate and some  want their own adjuster to write it  , Most Auto Body Shops will and can do that for you as well.