This android developer training tutorial could help - here's the basics:
Code to run in your Activity onCreate():
 // Create an instance of GoogleAPIClient.
    if (mGoogleApiClient == null) {
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
    }
    mGoogleApiClient.connect();
    LocationRequest mLocationRequest = new LocationRequest();
    mLocationRequest.setInterval(10000);
    mLocationRequest.setFastestInterval(5000);
    mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder()
            .addLocationRequest(mLocationRequest);
    PendingResult<LocationSettingsResult> result =
            LocationServices.SettingsApi.checkLocationSettings(mGoogleApiClient, builder.build());
    result.setResultCallback(new ResultCallback<LocationSettingsResult>() {
        @Override
        public void onResult(LocationSettingsResult locationSettingsResult) {
            final Status status = locationSettingsResult.getStatus();
            final LocationSettingsStates LS_state = locationSettingsResult.getLocationSettingsStates();
            switch (status.getStatusCode()) {
                case LocationSettingsStatusCodes.SUCCESS:
                    // All location settings are satisfied. The client can initialize location
                    // requests here.
                    break;
                case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
                    // Location settings are not satisfied. But could be fixed by showing the user
                    // a dialog.
                    try {
                        // Show the dialog by calling startResolutionForResult(),
                        // and check the result in onActivityResult().
                        status.startResolutionForResult(LocationByGPS.this, REQUEST_CHECK_SETTINGS);
                    } catch (IntentSender.SendIntentException e) {
                        // Ignore the error.
                    }
                    break;
                case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
                    // Location settings are not satisfied. However, we have no way to fix the
                    // settings so we won't show the dialog.
                    break;
            }
        }
    });
Override this Method:
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    final LocationSettingsStates states = LocationSettingsStates.fromIntent(data);
    switch (requestCode) {
        case REQUEST_CHECK_SETTINGS:
            switch (resultCode) {
                case Activity.RESULT_OK:
                    // All required changes were successfully made
                    GetUserLocation();//FINALLY YOUR OWN METHOD TO GET YOUR USER LOCATION HERE
                    break;
                case Activity.RESULT_CANCELED:
                    // The user was asked to change settings, but chose not to
                    break;
                default:
                    break;
            }
            break;
    }
}
Remember to Implement these in your class:
public class MyClass extends AppCompatActivity implements
    ActivityCompat.OnRequestPermissionsResultCallback,
    GoogleApiClient.ConnectionCallbacks,
    GoogleApiClient.OnConnectionFailedListener{
  protected static final int REQUEST_CHECK_SETTINGS = 0x1;
  /* 
     your code i.e. with the above code etc....
 */
 }
Good explanation here in this Google developer link.
Cheers!