Sub NumberParasTagged()
' Paul Beverley - Version 18.06.20
' Adds numbering to first-level headings tagged with <a>

myTag = "<a>"

titleLine = ActiveDocument.Paragraphs(1)
anglePos = InStr(titleLine, ">")
chapNumText = Mid(titleLine, anglePos + 1)
chapNum = Val(chapNumText)
secNum = 0

Set rng = ActiveDocument.Content
With rng.Find
  .ClearFormatting
  .Replacement.ClearFormatting
  .Text = myTag
  .Wrap = wdFindStop
  .Replacement.Text = ""
  .Forward = True
  .MatchWildcards = False
  .MatchWholeWord = False
  .MatchSoundsLike = False
  .Execute
End With

Do While rng.Find.Found = True
  endNow = rng.End
  rng.Collapse wdCollapseEnd
  rng.Select
  secNum = secNum + 1
  Selection.TypeText Text:=Trim(Str(chapNum)) & "." & _
       Trim(Str(secNum)) & vbTab
  rng.Start = endNow
  rng.Find.Execute
Loop
End Sub