"Xin" means Xin Bureau, that is, Water Affairs Bureau. "Xin enters the dry palace" is an inverted sentence, that is, "dry palace enters Xin", which means that the water bureau comes from the dry palace, the dry is the official position of the water bureau, and the dry side comes to the official water, which can be "ten thousand villages".
"Gui" means "Gui Bureau", which means "Gengui". It means that the Wood Bureau comes from Gen, Gen is the official position of the Wood Bureau, the Wood Bureau is not in Haimao, and Gen is the official position, so you can "send articles".