Rd Koons

Recently purchased a 2012 Cayenne Turbo that had its rear bumper and rear hatch cover damaged with no other apparent damage.Key was stuck in ignition, battery very low, pyroswitch blown, no voltage at jumper pins under hood. Replaced battery, pyro, and removed the key. Insurance company had taken all the interior apart looking for additional damage and totaled the car. I am searching for the current flow to the starter. Not sure what parts are involved and must be functional to start.