Section 120 direction reallocates jurisdiction to designated income tax authorities and prescribes their headquarters and scope. A directive under Section 120 vests specified powers and functions in named Income-tax authorities by designating their headquarters and delineating the classes of persons, incomes or territorial areas over which they shall exercise jurisdiction; it supersedes an earlier board notification subject to non-retroactivity, lists the commissioners and subordinate units in the Schedule, and states the notification's commencement and later amendments.