Update user guide tutorial (geojupyter#475)

* Update link to the shapefile layer in tutorial

* Update images in user guide tutorial

Author: elifsu-simula

docs/assets/images/CreateShapefileLayer.png

@@ -75,7 +75,7 @@ Follow along to add a vector layer available online.
    ![Open Layer Browser](../../assets/images/OpenLayerBrowser.png)
 3. Click on the **+** to add a user-defined layer and select "New Shapefile Layer" to add a new vector layer (stored as a shapefile).
    ![Add a Vector Layer](../../assets/images/addVectorLayer.png)
-4. Set the path of the new shapefile Layer to `https://public.opendatasoft.com/api/explore/v2.1/catalog/datasets/world-administrative-boundaries/exports/shp` and click **Ok**.
+4. Set the path of the new shapefile Layer to `https://public.opendatasoft.com/api/explore/v2.1/catalog/datasets/georef-united-states-of-america-county/exports/shp` and click **Ok**.
    ![Set Shapefile Layer](../../assets/images/CreateShapefileLayer.png)
 5. You will see the new Shapefile Layer on the map. When clicking on the **Custom Shapefile Layer** (see figure below), you will also see the details of the object properties on the right of the map. You can pan and zoom to focus on your area of interest, or automatically focus on your new data layer by right-clicking on the **Custom Shapefile Layer** and selecting "Zoom to Layer".
    ![View Shapefile Layer](../../assets/images/viewShapefileLayer.png)