In a Competitive OPL event, how many cards is a player required to bring?

In a Competitive OPL constructed event, a player is required to register a deck consisting of:

• Main Deck: Exactly 40 cards (including the Chosen Champion) (Rule 402.1).
• Legend: Exactly 1 card (Rule 402.1).
• Runes: Exactly 12 cards (Rule 402.1).
• Battlefields: Exactly 3 battlefields, all with unique names (Rule 402.1).

For sideboards, if a sideboard is used, it must be exactly 8 cards (FAQ 6411). Note that per Rule 401.4, your decklist must be registered prior to the start of the first round of competition.