How to calculate the date of funeral after death

Folk customs, people die, according to the date, usually 3 dates, or 5 dates! ,, the most important thing is for the deceased relatives chanting, chanting Buddha, crossing over,, this is the real interest,, the interests of ghosts and Yang! Believing in Buddhism, there is no such thing as choosing an auspicious occasion for a funeral, and there is no Amitabha in the south. . .