When workbook open, add a commandbutton to last sheet with macro command

Just copy this macro in the Thisworkbook VBA

Private Sub Workbook_Open()
Worksheets(ActiveWorkbook.Worksheets.Count).Select
ActiveSheet.Buttons.Add(199.5, 20, 81, 36).Select
Selection.Name = "New Button"
Selection.OnAction = "Macro1"
ActiveSheet.Shapes("New Button").Select
Selection.Characters.Text = "Press Me"
Selection.OnAction = "Macro1"
End Sub