How to export datagridview to docx using interop c#?

Question

Hi,

I'm trying to export the selected rows of a datagridview to a docx file with a specific header when I hit a button (a text and a date time picker which writes the current date):

Also note, every time I hit the button after selecting rows of the datagridview, the data(i.e. table) should be added to a new page of that same docx file with the same header format and not overwrite data.

I've done:

void Export2docClick(object sender, EventArgs e)
{
    //Table start.
    string html = "<table cellpadding='5' cellspacing='0' style='border: 1px solid #ccc;font-size: 9pt;font-family:arial'>";

    //Adding HeaderRow.
    html += "<tr><th colspan=3 style='background-color: #B8DBFD;border: 1px solid #ccc'>" + comboBox1.Text + "</th><tr>";
    foreach (DataGridViewColumn column in dataGridView1.Columns)
    {
        html += "<th style='background-color: #B8DBFD;border: 1px solid #ccc'>" + column.HeaderText + "</th>";
    }
    html += "</tr>";

    //Adding DataRow.
    foreach (DataGridViewRow row in dataGridView1.SelectedRows.OfType<DataGridViewRow>().OrderBy(s=>s.Index))
    {
        html += "<tr>";
        foreach (DataGridViewCell cell in row.Cells)
        {
            html += "<td style='width:180px;border: 1px solid #ccc'>" + cell.Value.ToString() + "</td>";
        }
        html += "</tr>";
    }

    //Table end.
    html += "</table>";

    //Save the HTML string as HTML File.
    string htmlFilePath = @"F:\checking\DataGridView.htm";
    File.WriteAllText(htmlFilePath, html);

    //Convert the HTML File to Word document.
    _Application word = new Microsoft.Office.Interop.Word.Application();
    _Document wordDoc = word.Documents.Open(FileName: htmlFilePath, ReadOnly: false);


    foreach (Microsoft.Office.Interop.Word.Section section in wordDoc.Sections)
    {
        //Get the header range and add the header details.
        Microsoft.Office.Interop.Word.Range headerRange = section.Headers[WdHeaderFooterIndex.wdHeaderFooterPrimary].Range;
        headerRange.Fields.Add(headerRange, WdFieldType.wdFieldPage);
        headerRange.ParagraphFormat.Alignment = WdParagraphAlignment.wdAlignParagraphCenter;
        headerRange.Font.ColorIndex = WdColorIndex.wdBlue;
        headerRange.Font.Size = 10;
        headerRange.Text = "Vizferma";
    }

    wordDoc.SaveAs(FileName: @"F:\checking\DataGridView.docx", FileFormat: WdSaveFormat.wdFormatXMLDocument);
    ((_Document)wordDoc).Close();
    ((_Application)word).Quit();

    //Delete the HTML File.
    File.Delete(htmlFilePath);
    MessageBox.Show("Done");
}

How do I add the header part and also how do I make the code paste data in a new page instead of overwriting the file every time?

Furthermore, how do I sort the selected rows of the datagridview by say, column 2 values in ascending order?

Thanks in advance