Start by heading to the location show on in this map view. When you arrive you will see a ruined tower. Walk halfway up the stairs and look out over the horizon.
Your view should match very closely to the map and look like the image below. You are now in the exact location of the view shown on your treasure map.
By comparing the X marker on your map to the view you currently have, you should have a good idea the location of the treasure. Take a mental picture and run over to the location. With any luck you should find a dirt mound.
If you have found the correct dirt mound an “E” prompt to dig will be available, and you can retrieve your treasure. Congrats on your find!