How in VBA in AutoCAD to set the paper size?

Sub Example_GetCanonicalMediaNames()
    ' This example gets the current plot device information
    ' and then displays the list of plot device names,
    ' media names, localized media names, and plot style
    ' table entries.
    Dim Layout As ACADLayout
    Set Layout = ThisDrawing.ModelSpace.Layout
    
    ' Refresh the current plot information for
    ' this session.
    Layout.RefreshPlotDeviceInfo
    
    ' List all the valid device names for the system
    Dim plotDevices As Variant
    plotDevices = Layout.GetPlotDeviceNames()
    
    Dim x As Integer
    For x = LBound(plotDevices) To UBound(plotDevices)
        MsgBox plotDevices(x)
    Next
    
    ' List all the media names, and their localized version
    Dim mediaNames As Variant
    mediaNames = Layout.GetCanonicalMediaNames()
    
    For x = LBound(mediaNames) To UBound(mediaNames)
        MsgBox mediaNames(x)
        MsgBox Layout.GetLocaleMediaName(mediaNames(x))
    Next
    
    ' List all the entries in the plot style table
    Dim styleNames As Variant
    styleNames = Layout.GetPlotStyleTableNames()
    
    For x = LBound(styleNames) To UBound(styleNames)
        MsgBox styleNames(x)
    Next
    
End Sub