//--- Create a new Worksheet
          PowerPointApplication ppta = new PowerPointApplication();
          Presentation pres = ppta.Create(PowerPointWriter.FileFormat.Pptx);
          Slide slide1 = pres.Slides[0];

          //--- Get an existing Worksheet by index
          PowerPointApplication ppta = new PowerPointApplication();
          Presentation pres = ppta.Create();
          Slide slide1 = pres.Slides[0];

          //--- Get an existing Worksheet by name
          PowerPointApplication ppta = new PowerPointApplication();
          Presentation pres = ppta.Create();
          Slide slide1 = pres.Slides["Slide1"];

          '--- Create a new Worksheet
          Dim ppta As New PowerPointApplication()
          Dim pres As Presentation = ppta.Create(PowerPointWriter.FileFormat.Pptx)
          Dim slide1 As Slide = pres.Slides(0)

          '--- Get an existing Worksheet by index
          Dim ppta As New PowerPointApplication()
          Dim pres As Presentation = ppta.Create()
          Dim slide1 As Slide = pres.Slides(0)

          '--- Get an existing Worksheet by name
          Dim ppta As New PowerPointApplication()
          Dim pres As Presentation = ppta.Create()
          Dim slide1 As Slide = pres.Slides("Slide2")