When used, a new dungeon location is activated on the world map, along with an indicator of the shortest path.
The entrance only spawns once the holder of the map reaches it, meaning it remains hidden from others up until that point. Once the location is discovered, the dungeon is fair game for all groups - so while the map's users will generally be the first to enter, they may not be the last.
Maps exist in the range of T4 - T8 with the possibility of uncommon, rare and exceptional variants. The mobs in the Randomized Dungeon the map will lead to will correspond to the Dungeon Map and the rarity will determine how many special and rare rooms can be found within the dungeon.