Adhering to DCI Sanctioned formats ensures a competitive playing field.
To play in a PL2 tournament, your deck must match the restrictions for that tournament's type.
Your deck and sideboard together may contain a total of only 4 cards with the same English name. Your deck must contain a minimum of 60 cards. Your sideboard must contain a maximum of 15 cards.
You can check a card's legality using Gatherer.
In limited events, you build a deck from sealed product. You can only play with cards that you open (when playing Sealed Deck) or draft (when playing Booster Draft). Your deck and sideboard together may contain any number of cards with the same English name. Your deck must contain a minimum of 40 cards. Your sideboard contains any other cards you received, which are not in your deck.