Dungeons & Dragons, or D&D for short, is a game of fantasy adventure. The game requires at least two participants, one or more players and one Dungeon Master. Many people find that the game plays best with five or six total participants.
Our purpose is to teach you the absolute basics of playing a D&D game as the Dungeon Master. Tutorials start presuming you know nothing. If you have previous experience playing D&D or another table-top role-playing game, you should look at the Resources.