path tracing on map in ios

Some one help me out please I am stuck on it from last few days...

My task is here.

In my app i need to integrate the map, as it open it should shows the current user position, as i pressed start button while walking it starts tracing path from the position where i pressed start button till the position i pressed stop.the distance covered in this interval should be traced turn by turn navigation and also wann to collect start and stop position coordinates to calculate distance.

i have added map kit framework, core location frame work, also added map view,and also implemented method to show current user position . now

here is my code

-(void)startSignificantChangeUpdates
  {
      // Create the location manager if this object does not
        // already have one.
        if (nil ==   self.locatioManager)
        {
           self.locatioManager = [[CLLocationManager alloc] init];
           self.locatioManager.delegate = self;
           [self.locatioManager startMonitoringSignificantLocationChanges]; 
        }
    }

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
    {
        // If it's a relatively recent event, turn off updates to save power
        CLLocation* location = [locations lastObject];
        NSDate* eventDate = location.timestamp;
        NSTimeInterval howRecent = [eventDate timeIntervalSinceNow];

        if (abs(howRecent) < 15.0) {
            // If the event is recent, do something with it.
            NSLog(@"latitude %+.6f, longitude %+.6f\n",location.coordinate.latitude,location.coordinate.longitude);
        }

        MKCoordinateRegion ref=MKCoordinateRegionMakeWithDistance([location coordinate], 250,250);
        [self.myMapView setRegion:ref animated:YES];
 }

Please guide me from here to trace path, and can collect coordinates also .