#1: After Hacking the first box, you have to turn around and find the second ctOS box way above the building there. Use the cameras to reach it. Next, get a vehicle and drive to the nearest building where the next ctOS box is found. Use the cameras to find it. The fourth ctOS box is located under the bridge. You can access it via foot. The last one is under the bridge. Go to the nearby docks and ride a boat. Once you’re in dry land, look up to find the last ctOS box and hack it to get an encrypted audio file.
#2: After Hacking the first box, you can find one ctOS box inside a parking garage across the street and one on the roof of a garage in the alley beside it. The next one is located conveniently along the sidewalk while the last one requires you to use a nearby camera to see and hack it.
#3: The first box is hidden behind the trash bin. The next one is located in the stairs in a structure nearby while the next one is beside a newspaper stand. The third box is located under the walkway and finally the last box is located in the rocky outcrop in the bay.