If you are trying to follow the Phenomenon Intel quests in Final Fantasy VII Rebirth, you will likely encounter the Modular Reactor series to gather all of Gelgamish’s artifacts. It’s important to mention that Phenomenon Intel Modular Reactor 3 requires you to be in Chapter 12 to start. The Goblin will call you and inform you when it is ready. If you are looking for the location of the cactuar rock, then don’t worry; it was indeed a bit confusing.
Following the cactuar light as the quest recommends will lead you to a big hole. You need to climb down to reach the mission’s cactuar rock. Simply go behind that hole, a little bit to the south, to find a ledge where you can go down. After a series of ledges to jump down through, you’ll reach that part. (see the map below)
