National Appellate Authority defined and linked to additional section references, expanding appellate scope under central GST law. The amendment adds the term National Appellate Authority into the appellate provision, directs that references to the Appellate Authority will include the National Appellate Authority, extends an existing cross reference to cover an additional provision, and inserts a definitional clause stating that National Appellate Authority means the National Appellate Authority for Advance Ruling as set out in the enabling provision.