public static void Run(
            String email,                               // authorization email
            String licenseKey,                          // authorization license key
            String openPath,                            // source PDF document
            String savePath                             // dest PDF document
            )
        {
            pdfix = new Pdfix();
            if (pdfix == null)
            {
                throw new Exception("Pdfix initialization fail");
            }

            if (!pdfix.Authorize(email, licenseKey))
            {
                throw new Exception(pdfix.GetErrorType().ToString());
            }

            PdfDoc doc = pdfix.OpenDoc(openPath, "");

            if (doc == null)
            {
                throw new Exception(pdfix.GetError());
            }

            // cleanup any previous structure tree
            if (!doc.RemoveTags(null, IntPtr.Zero))
            {
                throw new Exception(pdfix.GetErrorType().ToString());
            }

            // autotag document first
            if (!doc.AddTags(null, IntPtr.Zero))
            {
                throw new Exception(pdfix.GetErrorType().ToString());
            }

            // get the struct tree
            PdsStructTree struct_tree = doc.GetStructTree();

            if (struct_tree == null)
            {
                throw new Exception(pdfix.GetErrorType().ToString());
            }

            PdsStructElement paragraph = GetFirstParagraph(struct_tree);

            if (paragraph == null)
            {
                throw new Exception("No paragraph found.");
            }

            PdfRect annot_bbox = new PdfRect();

            GetStructElementBBox(paragraph, ref annot_bbox);

            // add new link annotation to the page
            PdfPage      page  = doc.AcquirePage(0);
            PdfLinkAnnot annot = page.AddLinkAnnot(0, annot_bbox);

            if (annot == null)
            {
                throw new Exception(pdfix.GetErrorType().ToString());
            }

            // re-tag the document the link annotation
            if (!doc.RemoveTags(null, IntPtr.Zero))
            {
                throw new Exception(pdfix.GetErrorType().ToString());
            }
            if (!doc.AddTags(null, IntPtr.Zero))
            {
                throw new Exception(pdfix.GetErrorType().ToString());
            }

            if (!doc.Save(savePath, PdfSaveFlags.kSaveFull))
            {
                throw new Exception(pdfix.GetError());
            }

            doc.Close();
            pdfix.Destroy();
        }