code: function setupHelpButton() {
      var command = commandRegistry.get(mindmaps.HelpCommand);
      command.setHandler(showHelp);
  
      var notifications = [];
      function showHelp() {
        // true if atleast one notifications is still on screen
        var displaying = notifications.some(function(noti) {
          return noti.isVisible();
        });
  
        // hide notifications if visible
        if (displaying) {
          notifications.forEach(function(noti) {
            noti.close();
          });
          notifications.length = 0;
          return;
        }
  
        // show notifications
        var helpRoot = new mindmaps.Notification(
            ".node-caption.root",
            {
              position : "bottomLeft",
              closeButton : true,
              maxWidth : 350,
              title : "This is your main idea",
              content : "Double click an idea to edit its text. Move the mouse over "
                  + "an idea and drag the red circle to create a new idea."
            });
  
        var helpNavigator = new mindmaps.Notification(
            "#navigator",
            {
              position : "leftTop",
              closeButton : true,
              maxWidth : 350,
              padding : 20,
              title : "This is the navigator",
              content : "Use this panel to get an overview of your map. "
                  + "You can navigate around by dragging the red rectangle or change the zoom by clicking on the magnifier buttons."
            });
  
        var helpInspector = new mindmaps.Notification(
            "#inspector",
            {
              position : "leftTop",
              closeButton : true,
              maxWidth : 350,
              padding : 20,
              title : "This is the inspector",
              content : "Use these controls to change the appearance of your ideas. "
                  + "Try clicking the icon in the upper right corner to minimize this panel."
            });
  
        var helpToolbar = new mindmaps.Notification(
            "#toolbar .buttons-left",
            {
              position : "bottomLeft",
              closeButton : true,
              maxWidth : 350,
              title : "This is your toolbar",
              content : "Those buttons do what they say. You can use them or work with keyboard shortcuts. "
                  + "Hover over the buttons for the key combinations."
            });
  
        notifications.push(helpRoot, helpNavigator, helpInspector,
            helpToolbar);
      }
    }
docs: Prepares notfications to show for help command.