I am able to get my results, but seems like there is a better way to do it.
doc.Element("XML").SetAttributeValue("Type", "ListBuilder");
doc.Element("XML")
.Element("Order").SetAttributeValue("No", 425654);
doc.Element("XML")
.Element("Order").SetAttributeValue("DispDate", today);
doc.Element("XML")
.Element("Order").SetAttributeValue("Basket", 3536);
