Appellate Tribunal procedure: power to regulate its own process and exercise civil court powers in GST appeals. Section 111 provides that the Appellate Tribunal, guided by principles of natural justice, may regulate its own procedure and, while not bound by the Code of Civil Procedure, shall have specified civil court powers (including summons, discovery, affidavits, requisitioning public records, commissions, and default/dismissal powers). Its orders are enforceable as court decrees through competent civil courts, and proceedings before it are deemed judicial proceedings for applicable penal and criminal procedure provisions.