How to convert XML columns to rows in SQL database?

Question

I am trying to import an XML invoice to SQL database. After some research, I have managed to put it in SQL database but it has x rows whereas it should be a single row and x columns. Most of the sources I have read had examples of XML tables with multiple rows and XML files themselves were much simpler than this invoice file I am working with. I am aware the issue is probably related with columnMapping but could not figure how to fix it. Any help is appreciated.

Unfortunately I can't share the original invoice but I have found something similar: http://docs.oasis-open.org/ubl/os-UBL-2.2/xml/UBL-Invoice-2.1-Example.xml

 private void buttonImport_Click(object sender, EventArgs e){
                string XMlFile = textBoxBrowse.Text;
                if (File.Exists(XMlFile))
                {
                    DataTable dt = CreateDataTableXML(XMlFile);
                    if (dt.Columns.Count == 0)
                        dt.ReadXml(XMlFile);

                    string Query = CreateTableQuery(dt);
                    SqlConnection con = new SqlConnection(strcon);
                    con.Open();

                    cmd.ExecuteNonQuery();

                    // Table Creation  
                    cmd = new SqlCommand(Query, con);
                    int check = cmd.ExecuteNonQuery();
                    if (check != 0)
                    {
                        // Copy Data from DataTable to Sql Table  
                        using (var bulkCopy = new SqlBulkCopy(con.ConnectionString, SqlBulkCopyOptions.KeepIdentity))
                        {
                            foreach (DataColumn col in dt.Columns)
                            {
                                bulkCopy.ColumnMappings.Add(col.ColumnName, col.ColumnName);            }

                            bulkCopy.BulkCopyTimeout = 600;
                            bulkCopy.DestinationTableName = dt.TableName;
                            bulkCopy.WriteToServer(dt);
                        }

                        MessageBox.Show("Table Created Successfully");
                    }
                    con.Close();
                }
            }

    public DataTable CreateDataTableXML(string XmlFile) {
                XmlDocument doc = new XmlDocument();

                doc.Load(XmlFile);

                DataTable Dt = new DataTable();

                try
                {
                    Dt.TableName = GetTableName(XmlFile);
                    XmlNode NodeStruct = doc.DocumentElement.ChildNodes.Cast<XmlNode>().ToList()[0];

                    foreach (XmlNode columna in NodeStruct.ChildNodes)
                    {
                        Dt.Columns.Add(columna.Name, typeof(String));
                    }

                    XmlNode Files = doc.DocumentElement;

                    foreach (XmlNode File in Files.ChildNodes)
                    {
                        List<string> Values = File.ChildNodes.Cast<XmlNode>().ToList().Select(x => x.InnerText).ToList();
                        Dt.Rows.Add(Values.ToArray());
                    }
                }
                catch (Exception ex)
                {
                }
                return Dt;
            }