public Map GetMap()

//Create a map frame and set its camera by zooming to the extent of an existing bookmark.

//Construct on the worker thread
await QueuedTask.Run(() =>
{
  //Build 2D envelope geometry
  Coordinate2D mf_ll = new Coordinate2D(6.0, 8.5);
  Coordinate2D mf_ur = new Coordinate2D(8.0, 10.5);
  //At 2.x - Envelope mf_env = EnvelopeBuilder.CreateEnvelope(mf_ll, mf_ur);
  Envelope mf_env = EnvelopeBuilderEx.CreateEnvelope(mf_ll, mf_ur);

  //Reference map, create MF and add to layout
  MapProjectItem mapPrjItem = Project.Current.GetItems<MapProjectItem>()
                       .FirstOrDefault(item => item.Name.Equals("Map"));
  Map mfMap = mapPrjItem.GetMap();
  Bookmark bookmark = mfMap.GetBookmarks().FirstOrDefault(
                        b => b.Name == "Great Lakes");

  //At 2.x - MapFrame mfElm =
  //                  LayoutElementFactory.Instance.CreateMapFrame(
  //                                             layout, mf_env, mfMap);
  //         mfElm.SetName("New Map Frame");
  //
  MapFrame mfElm = ElementFactory.Instance.CreateMapFrameElement(
                       layout, mf_env, mfMap, "New Map Frame");

  //Zoom to bookmark
  mfElm.SetCamera(bookmark);
});

public static async Task<Map> FindOpenExistingMapAsync(string mapName)
{
  return await QueuedTask.Run(async () =>
  {
    Map map = null;
    Project proj = Project.Current;

    //Finding the first project item with name matches with mapName
    MapProjectItem mpi = proj.GetItems<MapProjectItem>()
      .FirstOrDefault(m => m.Name.Equals(mapName, StringComparison.CurrentCultureIgnoreCase));
    if (mpi != null)
    {
      map = mpi.GetMap();
      //Opening the map in a mapview
      await ProApp.Panes.CreateMapPaneAsync(map);
    }
    return map;
  });

}