This version is an early stage of the modpack/map. The final version will have many more rooms for you to explore.
"Rooms" is a map which is split into sections. In order to progress to the next section, you will have to explore miniature worlds, solve complex puzzles, or do something else. To reach the end (of the finished map) you will have to be skilled in fighting, parkour, problem solving and you will also have to use your knowledge of mods, commands and redstone.
...or you could just play with a friend who is more experienced than you...