This is related to the task where Rufus needs to line up his harpoon with the Organon tracks. On the screen will be an eight-directional joystick that you need to move into the right position and then confirm. However, the controls aren't immediately understandable and shift about the reticle far too easily. The shortest solution to getting this trophy, and lining up the sights, relates to moving the joystick in the proper positions.
Starting from the top, the available positions are 1 (north-northeast), 2 (east-northeast), 3 (east-southeast), 4 (south-southeast), 5 (south-southwest), and 6 (west-southwest). Positions 7 and 8 are blocked off by a piece of wood covering them, otherwise it'd be easier to access the point you needed. The order you need to move the joystick and confirm are: 6, 1, 6, 1, 6, 4, 1, 6, 1.
The difficulty comes in that you have to make sure you get this trophy without exiting the puzzle, skipping the puzzle, or (not sure on this part) resetting.