At Nats, Booster is played by giving all participants a FooF or RoA tin, whichever major booster is missing (Pats or Kings), and the latest release (Disciples this year).
Each player looks at the tin's set of 10 cards, then open the originals pack and begin to draft by choosing one card, passing it to the next player, and choosing a card from the previous player's booster. This continues until all players have drafted all cards from the packs. Prophets is next, then Apostles, Pats, Kings, Priests, and then Disciples.
Once drafted, you must make a deck out of your cards that adheres to lost soul building rules. You then play several rounds of something like T1MP with the deck you made.