Hi, here’s the solution:
Start from the beginning and choose only Mert or Artyom. In the movies, pick the family movie for Mert and the horror movie for Artyom. When choosing an outfit for Finn, pick one cap, one pair of pink boxers, and one pair of sneakers. Make sure they get hard after seeing it. That’s it. When you get to the island and the map opens, a new option will appear for each of them.