You have to arrange 15 cards to find the coordinates. The blue numbers in the middle are a single digit in the coordinates, around the corners of the cards are clues on how to put them in order. The final is a 2Lt Sistema.
Please note you can take the cards off the link to get them in the right order, they do not need to go back in any particular order, see the gallery for an example card. Co-ords are +/- 8m due to tree cover. I would not recommended going into the bush at night.
Any logs that indicate how to solve the puzzle will be deleted, you may relog your find without any online spoilers.