Special Provisions
Where Article 356 has transferred a State's legislative power to Parliament: (a) Parliament can delegate that law-making power to the President, who can further delegate it (with conditions) to another authority; (b) whoever holds that power can confer powers/duties on the Union; (c) the President can authorise Consolidated Fund of the State expenditure when the Lok Sabha isn't in session, pending Parliament's sanction. Laws made this way continue after President's Rule ends, until a proper Legislature changes them.
This spells out the practical mechanics of how a state actually gets governed once its own Legislature's powers are taken over under Article 356 - typically Parliament delegates the actual day-to-day law-making to the President, who in turn often delegates it further, letting the state's laws still get made (just through this substitute Union-controlled process) rather than the state having no functioning legislative process at all during President's Rule.
During President's Rule, a state's budget and other laws are typically passed via this delegated mechanism - often through Parliament passing the state's budget directly, or the President (via a delegate) issuing state-level regulations that would normally have come from the state's own Legislative Assembly.