ios - How does MKMapView's showsUserLocation work?

As the mac desktop's simulator don't have location service, I can't try by myself and I choose to ask here.

the google map app can do continuous locationing for your device, as you move you can see the blue spot moving on the map.
But how can we develop app that does it?
Is it just
(1)enable the device location service in setting.
(2)add the codes: mapView.showsUserLocation = YES;

sufficient to do this? If yes, can we know how frequent does it update the location?

the similar query also raised on CLLocationManager class and its delegate.
how startUpdatingLocation method updates the device's location? and how frequent is it?
And, does startUpdatingLocation call the locationManager: didUpdateToLocation?
how does the former call the latter and what to implement in the latter?