Hi Jana,
The way it created in the sample is to create an extent out of the results which mostly more than one location then zoom to that extent.
In your case I believe you have only one point as a result to zoom to, so here is the way to zoom and center a point, you can change the scale value as desired.
await MyMapView.SetViewAsync(_graphicsOverlay.Graphics[0].Geometry);
await MyMapView.ZoomToScaleAsync(560);
Thanks,
Asser