Can you explain how the power of Parliament concerning goods and services tax works according to this text?
The power of Parliament concerning goods and services tax works as follows:

According to Article 246A, Parliament has exclusive power to make laws with respect to goods and services tax where the supply of goods or of services, or both takes place in the course of inter-State trade or commerce. This means that only Parliament can legislate on taxes related to such supplies across states.

The Explanation provided further clarifies that these provisions will apply to the goods and services tax mentioned in Article 279A from a date recommended by the Goods and Services Tax Council, which implies that there is some coordination between the Parliament and the council for setting the effective date of this legislation.