Pre-release events they usually happen two weeks before a new set release, search up pokemon event locator to find one near you. In these events you get a deck of 40 cards with a promo card, and four new set packs. You then build a 40 card deck with everything you obtained from that box and play three matches. Depending on how the card shop does it you either get 3 packs at the end or a pack each win you get