Vista Points are a little more involved in Horizon Forbidden West than they were in the first game. When you reach a Vista Point on the map, you will be given a partial hologram of the Vista Point, and you'll need to line it up with somewhere in the surrounding area to complete the image. To view the hologram, use your Focus. When it lines up with the correct spot, you'll solve the Vista Point, and be able to view it whenever you like.