Welcome adventurer!
The Desert Citadel is a classic CTM (Complete The Monument) map, where the player(s) must collect at least one of each pieces of wools, and place them in their corresponding place on the Victory Monument. By classic, the creator (that's me) means that command blocks are not a viral part of the map. They are used for some fancy stuff only - by which the creator means: mostly traps.
The Desert Citadel is an open world map, the first barrier players will face is finding the islands which the dungeons are located on. The creator (again, that would be me) helps the players in their journey with different clues and waypoints.
The Desert Citadel facilitates custom mobs, loot chests, unique weapons, shields and armor with different attributes, custom terrain, relics, custom spawners, local bosses etc.. The creator thinks that his map is not very difficult (but he's the creator of it, duh).