How to create a simple diagram with symbol palette?

public ActionResult DefaultFunctionalities()
            {
                // Creates a collection of nodes to be displayed in the diagram
                List<DiagramNode> nodes = new List<DiagramNode>();
                //…                
                nodes.Add(new DiagramNode()
                {
                    Id = "NewIdea", OffsetY = 80,
                    OffsetX = 340,
                    Height = 60,
                    Annotations = Node1,
                    Shape = new { type = "Flow", shape = "Terminator" }
                });
                //…
                // Creates a collection of connectors to be displayed in the diagram
                List<DiagramConnector> Connectors = new List<DiagramConnector>();
                Connectors.Add(new DiagramConnector() { Id = "connector1", SourceID = "NewIdea", TargetID = "Meeting", });                           
                 //…
                List<Syncfusion.EJ2.Diagrams.DiagramNode> flowShapes = new List<Syncfusion.EJ2.Diagrams.DiagramNode>();
                // Adds a node into the flowShapes collection.
                flowShapes.Add(new DiagramNode() { Id = "Terminator", Shape = new { type = "Flow", shape = "Terminator" } });
                //…
                List<DiagramConnector> SymbolPaletteConnectors = new List<DiagramConnector>();
                // Adds a connector into the SymbolPaletteConnectors collection.
                SymbolPaletteConnectors.Add(new DiagramConnector()
                {
                    Id = "Link1",
                    Type = Segments.Orthogonal,
                    SourcePoint = new DiagramPoint() { X = 0, Y = 0 },
                    TargetPoint = new DiagramPoint() { X = 40, Y = 40 },
                    TargetDecorator = new ConnectorTargetDecoratorConnectors() { Shape = DecoratorShapes.Arrow },
                    Style = new DiagramStrokeStyle() { StrokeWidth = 2 }
                });
                //…
            }