Set up a vehicle
Where the log starts
Set the starting odometer (Garage → Edit → Where the log starts) only if the tank was full at that reading (a new car delivered with a full tank: 0, or its delivery mileage). Otherwise leave it blank: the first full fill-up is where the log starts.
An electric car
An electric car’s starting point is in By drivetrain.
Bought with a full tank
Give the odometer when bought (Garage → Edit → Purchase) and leave Full tank when bought on: the log starts at the purchase, so a new car’s first tank counts from 0. Turn it off when the tank wasn’t full, and the first full fill-up starts it.
Its odometer reads
Under it, Its odometer reads is your units unless you pick Miles or Km, for a car whose dash reads the other one (one shipped from abroad). Every odometer for it is then typed and shown in that unit, while distances and economy stay in yours.