Customs Tariff amendment updates the First Schedule through staged schedule-based changes, altering tariff entries and phased implementation. Amendment of the First Schedule to the Customs Tariff Act directs staged revisions: specified modifications in a Second Schedule, further changes to take effect from the start of the subsequent financial year as set out in a Third Schedule, and additional amendments commencing on a later stated date as detailed in a Fourth Schedule, each altering the First Schedule's tariff classifications and entries as prescribed.