Option Explicit

Private Sub Document_ContentControlOnEnter(ByVal ContentControl As ContentControl)
    Select Case ContentControl.Title
        Case "ccHW"
            If ContentControl.Checked Then
                FillBM "HW", "This is the content of bookmark HW"
            Else
                FillBM "HW", ""
            End If
        Case "ccCS"
            If ContentControl.Checked Then
                FillBM "CS", "This is the content of bookmark CS"
            Else
                FillBM "CS", ""
            End If
    End Select
End Sub

Private Sub FillBM(strBMName As String, strValue As String)
'Graham Mayor - http://www.gmayor.com
Dim oRng As Range
    With ActiveDocument
        On Error GoTo lbl_Exit
        Set oRng = .Bookmarks(strBMName).Range
        oRng.Text = strValue
        oRng.Bookmarks.Add strBMName
    End With
lbl_Exit:
    Set oRng = Nothing
    Exit Sub
End Sub