GST rules amend valuation, invoicing, input tax credit procedures, returns matching, refunds and transitional credit processes. The Rules set out hierarchical determination of value for non-monetary and related-party supplies, detailed documentary and procedural conditions for claiming and reversing input tax credit (including attribution formulas, ISD distribution, bank/financial institution rules and job-worker provisions), prescriptive invoice/delivery challan and record-keeping standards, comprehensive returns and electronic matching and rectification processes, ledger-based payment and refund mechanics with prescribed formulas, and transitional filings, audit, assessment and appeal procedures to operationalise GST compliance in Gujarat.