Need som PD help..

ok so i started playing Pandora again, to do all the puzzles and stuff.. now i just got the box with the Maya dates on.. you know the one with the Maya dates on the right and the modern on the left. Now, i understand it and all but i just cant find the logic to it.. i used youtube to find the first number just so i might be able to figure out the rest of it, but it still dont make any sence.. the first one was AHUA 4, witch was 8 of sep, and since the picture was the 9 in the order and 2x4 for the date.. but when it came to the next one and tryed to apply this it dident work.. so i crawled back to the cross and looked at the sulution for the second one and it was may the 20, but the symbole was the 11th but for the date it worked with 10 (from the sybole), but the month dident. OK maybe im just confusing myself but i realy want to understand it :P PLEASE HELP me understand this :P
It's really simple conversion and math once you have all the information. I couldn't find any errors with the puzzle. However I don't recall if February accounted for the leap year.
aha so i have to calculate the whole year.. oki that makes sence, damn then i have to birng pen and paper :P thanks :) il try this next time i work night :P

PS. I might come back with tis on a later point in time when i try it out :P me and math dont se eye to eye :P