How to Find and Enter a Better Dungeon
Locating the Entrance
Better Dungeons replace the vanilla dungeon structure, so the fastest way to find one is to keep exploring the same places you would normally look for a monster spawner room. Dig into cave systems, ravines, and the bases of hills where a cobblestone-and-mossy-cobblestone outline appears. The entrance is usually a built doorway or stairwell rather than a bare hole, so watch for deliberate stone brick and cobblestone framing instead of natural cave walls.
Once you spot the entrance, do not tunnel straight through the wall. Follow the built corridor inward — the layout branches, and breaking through walls can drop you into a lower floor without a way back up.
Preparing Before You Go In
Bring a full set of iron or better armor, a stack of torches, a pickaxe for cobblestone and stone bricks, and blocks to pillar or bridge with. Carry a water bucket for falls and a bed or spare blocks to mark your route. Because the dungeon is multi-level, place torches on the right-hand wall as you descend so you can retrace your path.
Light every room as you enter it. Spawners and dark corners are the main threat, and clearing light first lets you fight on your terms. If a corridor dead-ends, check the floor and ceiling — the route often continues vertically rather than straight ahead.