Secondary rules are for recognizing and enforcing the primary rules thereby in providing remedy. They are what Hart calls power-conferring rules. They state the manner in which primary rules may be acknowledged, transformed and adjudicated. For example - the power to legislate and private citizens the right to vote. Legislature one must follow the procedure in order to make a legal will. Secondary rules are, as Hart puts it, "rules about primary rules."
Rules of recognition- (law making/executing/interpreting power)
Rules of change (amendment/review)
Rules of Adjudication (judicial rulings/activism)
When Primary rules impose duties upon the citizen not to violate the particular legal rules at issue, secondary rules confer power upon the lawmaker/adjudicator to officially approve the legal disobedient in a manner in accordance with his or her authorized power.