The ActiveLayer property returns the active Layer on the active page in the active document.
Examples:
The following VBA example creates an ellipse on the active layer in the current document.
Sub LayerActive()
ActiveLayer.CreateEllipse 3, 3, 2, 1
ActiveDocument.Selection.Shapes(1).Fill.UniformColor.CMYKAssign 100, 0, 100, 0
'Fills the ellipse green
End Sub