C# .docx to .pdf convesion

WordToPDFProgram.cs

using System;
using System.IO;

//wordtopdf.dll downloaded from https://www.c-sharpcorner.com/uploadfile/698727/convert-word-file-to-pdf-using-c-sharp/
using WordToPDF; 

namespace WordPDFConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            // The code provided will print ‘Hello World’ to the console.
            // Press Ctrl+F5 (or go to Debug > Start Without Debugging) to run your app.
            
            // Go to http://aka.ms/dotnet-get-started-console to continue learning how to build a console app! 

            Word2Pdf objWorPdf = new Word2Pdf();
            //string backfolder1 = "D:\\WOrdToPDF\\";
            string backfolder1 = @"C:\Users\Arthur\WordToPDFFiles\";
            string strFileName = "TestMemoDoc - Copy.docx";
            object FromLocation = backfolder1 + "\\" + strFileName;
            string FileExtension = Path.GetExtension(strFileName);
            string ChangeExtension = strFileName.Replace(FileExtension, ".pdf");
            if (FileExtension == ".doc" || FileExtension == ".docx")
            {
                object ToLocation = backfolder1 + "\\" + ChangeExtension;
                objWorPdf.InputLocation = FromLocation;
                objWorPdf.OutputLocation = ToLocation;
                objWorPdf.Word2PdfCOnversion();
            }

            Console.WriteLine("Hello... Document Converted!");
            Console.ReadKey();
        }
    }
}

Error: {"Referencia a objeto no establecida como instancia de un objeto."}
when I execute 'objWorPdf.Word2PdfCOnversion();'

Well, ensure you set a reference to the object before calling it. You may also use these gists:
https://gist.github.com/ArthurEzenwanne/c443e8bbc67af312aea05c632652ab56
https://gist.github.com/ArthurEzenwanne/fa5d4d2d651081b39071f1883fe6619c