How to arrange the document tabs in different position in the DockingManager?

<Window x:Class="Dockable_Property.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:syncfusion="http://schemas.syncfusion.com/wpf"
        Title="MainWindow" Height="350" Width="525">
  <Grid>
    <syncfusion:DockingManager Name="Docking" UseDocumentContainer="True" Loaded="Docking_Loaded" >
    </syncfusion:DockingManager>
  </Grid> 
</Window>

using Syncfusion.Windows.Tools.Controls;
namespace Dockable_Property
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }      
       private  void Docking_Loaded(object sender, RoutedEventArgs e)
        {
            ContentControl child1 = new ContentControl();
            DockingManager.SetState(child1, DockState.Document);
            DockingManager.SetHeader(child1, "Child1");            
            ContentControl child2 = new ContentControl();
            DockingManager.SetState(child2, DockState.Document);
            DockingManager.SetHeader(child2, "Child2");
            ContentControl child3 = new ContentControl();
            DockingManager.SetState(child3, DockState.Document);
            DockingManager.SetHeader(child3, "Child3");
            ContentControl child4 = new ContentControl();
            DockingManager.SetState(child4, DockState.Document);
            DockingManager.SetHeader(child4, "Child4");
            Docking.Children.Add(child1);
            Docking.Children.Add(child2);
            Docking.Children.Add(child3);
            Docking.Children.Add(child4);
//The following code shows how to set the TDIIndex for the Document children that arrange the document tabs in different position according to the index provided
            TDILayoutPanel.SetTDIIndex(child1, 0);
            TDILayoutPanel.SetTDIIndex(child2, 3);
            TDILayoutPanel.SetTDIIndex(child3, 1);
            TDILayoutPanel.SetTDIIndex(child4, 2);      } }
        }