Quarterly tax payment procedure requires CMP-08 quarterly filing and annual GSTR-4 return, constituting deemed compliance with return obligations. Composition scheme taxpayers or those availing the Kerala notification must file quarterly self-assessed tax statements in Form GST CMP-08 by the 18th of the month following each quarter and an annual return in Form GSTR-4 by April 30; submission of these forms constitutes compliance with the statutory return obligations for the relevant periods; the procedure applies from April 23, 2019.