Of course you will not proceed here unless you have managed to get through all my pages describing the week and the month. You start with the week (from a to c), then go on with the month in a similar way, and after that you will be prepared for the year.
The Maya Indians had a sacred year covering 260 days. Nobody seems to know exactly why (Coe, Ifrah). But I think I have a natural explanation: They tried their best to discover The General Theory of Everything, i.e. how Time-Space was constructed. There are 26 double-weeks in a year and therefore 260 is a reasonable attempt to harmonize the sacred periods of Week and Year.
Double-weeks (instead of single weeks) were - I believe - also used in order to harmonize: If the world is constructed so that we need to count two Moon cycles, then we probably had better count two sacred Weeks also.
(Watching planets is done in the night, not during the day. Therefore the word 'fortnight'. Polynesians do not count days, they count nights.)
The calendar in Small Santiago Tablet is - I suspect - also built on double-weeks, and with 26 such we reach 364. In all there are 31 partitions in this tablet, but 3 of them, in the beginning, seem to be special and perhaps are 'outside' of the sacred Year.
And in partition no. 31 we can read that 26 is The Number. I therefore guess that partition no. 31 too is on the outside of the sacred Year.
Partition no. 30 is a special case, because after passing 364 nights there still remains 1 night.