You can only activate this card while there are 5 face-up Level 2 or lower Normal Monsters on your side of the field. Both players discard all cards in their hands, and destroy all cards on the field except Level 2 or lower Normal Monsters.
Rulings
Individual Card FAQs
The "Law of the Normal" includes Tokens.
The "Law of the Normal" also destroys all Spell & Trap Cards.
The requirement to have 5 face-up Level 2 or lower Normal Monsters only has to be met when "Law of the Normal" is activated, not when it resolves.