Begin at the posted coordinates. When you get there, match the mural at that location to the corresponding picture in the cache page gallery. The picture contains partial coordinates (e.g., .123 .456). To obtain the coordinates for the next stage, change the last 3 digits of the North and West posted coordinates to the numbers on the mural's picture. Repeat this process for each stage and you'll get a smiley at stage 5!
If you'd like to know more about the murals of Kaka'ako, use your favorite seach engine to find the Pow! Wow! Hawaii website.