The Dungeon Master’s Guide teaches you how to create entire D&D worlds for your players to explore.
It walks you through the essential elements of a good adventure and shows you how to be the architect of a fun campaign that your players are sure to remember.
It also helps you adjudicate the rules in a variety of situations and gives you the tools you need to improvise when the players lead the story in unexpected directions.
Play all of the surrounding characters in the adventure and add flavour to interactions with your adventurers!