To find out if the ID.3 is currently charging or if it has finished charging, check the LED display under the windscreen (also visible from outside the vehicle). It also shows how much the vehicle has been charged.
The car otherwise charges normally: plug the charging cable into the car and the charging station. Hold your tim card up to the charging station to confirm. Then check to ensure that the car is charging. This will be indicated by a flashing green light on the connector on the car.
