Yeah I sadly ran out of time to include a better tutorial. I'm glad you liked the concept though!
So in case you are interested, here's a bit more explanation how it should work: The goal is to map the whole island, not only the landmarks. They are just there to have good points you can orient yourself with. The idea is that you look at a landmark and see "oh that's at 70°", then you open the map and place the ruler with the small gray circle on the landmark, so that it rotates around the landmark. Thats also why the degree display is offset by 180, because it assumes you measure from the landmark. If you want to see an example, feel free to view the video on the game page.
Thanks for playing!