C# - WPF - Coecting code-behind with XAML elements

This question is a little coected with the previous one here

Generally I write an application which allows user to create his own graph and then get the shortest path. I got stucked with graphical representation.

I've rarely used XAML and have no idea how to coect methods in code-behind with XAML code.

I get the coordinates of mouse click in Canvas and it works great

private void mouseDoubleClick(object sender, MouseButtonEventArgs e)
    {

        int x = (int)e.GetPosition(dataCanvas).X;
        int y = (int)e.GetPosition(dataCanvas).Y;
        currentMap.CreateNodes(x, y, "ExampleNode");
        targetText.Text = x.ToString() + "X " + y.ToString() + "Y "; // Just for debugging
    }

Here is the CreateNode definition:

public void CreateNodes(int x, int y, string name)
    {
        Node node = new Node(name);

        this.places.Add(node);

        node.X = x;
        node.Y = y;

        GUI.CreateNode(node);
    }

But problem is still here

//GUI class
    public static void CreateNode(Node n)
    {
        Point point = new Point(n.X, n.Y);
    }

This method should draw the image in the specific (x, y) place. I have the coordinates and have to somehow create an image there. As I said I'm not fluence with using XAML and don't know how to coect this code with adjusting canvas in XAML to create and manipulate an image.

I was given a link here

but I'm not sure how to use it in my project. Am I supposed to create an ObservableCollection and then use the code from the link...?

Any help would be appreciated.

Here you have the interface: here