Sets or returns an int that represents the number that the line numbering starts at for this section.

 public int FirstLineNum{ get; set; }
Public Property FirstLineNum() As Integer

MS Word equivalent: File menu > Page Setup... > Layout tab > Line Numbers... button > Start at: -- (Make sure Apply to: This section is selected)

          //--- Return FirstLineNum
          int firstLineNum = oSection.FirstLineNum;

          //--- Set FirstLineNum
          oSection.FirstLineNum = 2;

          '--- Return FirstLineNum
          Dim firstLineNum As Integer = oSection.FirstLineNum

          '--- Set FirstLineNum
          oSection.FirstLineNum = 2