"check possible installation location" "I feel it in the water"

[Sometimes Gamer]

I do not understand what I am supposed to do to "check possible installation location" for the expedition "I feel it in the water". I see that I can move the green dot around but what is the right location? Am I just guessing? being guided? supposed to just know?

[j-m.c]

You have to check three locations. Go to https://3d.maprunner.info/ for help.