Board's power to issue instructions shapes tax administration while safeguarding appellate discretion and permitting limited procedural relief. The Board may issue orders, instructions and directions to income-tax authorities for proper administration, including publishing general or special orders setting guidelines for assessment, collection and penalty proceedings. These powers do not permit directing a particular assessment or interfering with the appellate discretion of the Joint Commissioner (Appeals) or Commissioner (Appeals). To avoid hardship the Board may authorise non-appellate authorities to admit belated claims and may relax certain procedural requirements where default was beyond the assessee's control and compliance occurs before completion of assessment.