How does clause (3) specify jurisdiction, powers and authority for tribunals?
Clause (3) specifies jurisdiction, powers and authority for tribunals in the following ways:

(a) A law made under clause (1) may provide for the establishment of a hierarchy of tribunals. This implies that there can be different levels or types of tribunals created by the law to handle specific matters or issues.

(b) The same clause also specifies that the law may specify the jurisdiction, powers, and authority which may be exercised by each of the said tribunals. This means that the law will determine what kinds of cases or disputes a particular tribunal can handle, as well as what kind of decisions it can make and how much power it has to enforce those decisions.

(c) Lastly, clause (3) states that the law may provide for the procedure (including provisions as to limitation and rules of evidence) to be followed by the said tribunals. This means that the law will set out the legal procedures that must be followed when a case is brought before a tribunal, including any time limits for bringing cases and what kinds of evidence can be used in making decisions.