Stage 1: Go to the posted coordinates and count the # of vertical posts that you see which are supporting the structure that you are standing on. This number will be A.
Multiply A times 13.25. Call you answer B
Stage 2: You will see a man made object here. It has three metal tags attached to it. Look at the words on the top, oval shaped tag. How many letters are in the first two words on the tag? Call that number C.
Multiply C times 16. Call that # D.
Stage 3: Start at stage 2 and project a waypoint from stage 2 a distance of D ft at a bearing of B degrees.
You are looking for a small round container. It is hidden pretty well. Make sure that you re-hide it with the "natural" so that it stays muggle free.