Need help with passage and priorities (RPGM-XP)

Ok so, Im relatively new to using RPGM xp, and I came across Inquisitors amazing tilesets, I figured out how to import
and it to the database, I understand how to set the passage, but with priority Im slightly confused, Im just looking for a good explanation of how it works, and on a side note, whether I should have to do this, thought maybe someone setup
the passage and priority for these tilesets already and i just dont know how to import the file to have it setup already.
I probably sound like a total Noob, but there are alot of tilesets, and after setting passage and priority for Inquisitors,
world map set, I felt like my hand might fall off, lol

any help will be appreciated ;P

Eleecho
(Here lies Erdrick)