Create ERD, Add Entities & Relationships using VBA

I saw this example on site "http://visio.mvps.org/VBA.htm"

Dropping a Master: This subroutine will drop a master on the page.

You need to get a Master or Shape object to drop on the page before calling
the Drop method. The example below drops the Circle shape from the Blocks
Raised stencil on the current drawing page.
Public Sub TestDropShape()
Dim stencil As Visio.Document, mstCircle As Visio.Master
Set stencil = ThisDocument.Application.Documents.Open("Blocks Raised.vss")
ThisDocument.Application.Windows(ThisDocument.Index).Activate
Set the ActiveWindow to the drawing window.
Set mstCircle = stencil.Masters("Circle") ' Get the master named "Circle"
and drop that shape on the page!
ThisDocument.Pages(1).Drop mstCircle, 1, 3 ' Drop the shape, mstCircle, at
location X=1 Y=3
End Sub