As with any religion they have guidelines that they follow too. Shinto is an ancient Japanese religion. Its name was derived from the Chinese words "shin tao" ("The Way of the Gods") in the 8th Century CE. Shinto has a basic optimism about human nature, and for the world. Shinto does not have as fully developed a theology as do most other religions. It does not have its own moral code. Shintoists generally follow the code of Confucianism. All of humanity is regarded as "Kami's child." Thus all human life and human nature is sacred. Believers revere "musuhi", the Kamis' creative and harmonizing powers. They aspire to have "makoto", sincerity or true heart. This is regarded as the way or will of Kami.Morality is based upon that which is of benefit to the group. "Shinto emphasizes right practice, sensibility, and attitude." There are "Four Affirmations"in Shinto Tradition and the family: The family is seen as the main mechanism by which traditions are preserved. Their main celebrations relate to birth and marriage. Love of nature: Nature is sacred; to be in contact with nature is to be close to the Gods. Natural objects are worshipped as sacred spirits. Physical cleanliness: Followers of Shinto take baths, wash their hands, and rinse out their mouth often. "Matsuri": The worship and honor given to the Kami and ancestral spirits. http://www.religioustolerance.org/shinto.htm

A more direct answer is that they do not. Or, rather, Shinto is not used to determine right and wrong. Shinto is not a law-giving or morality-giving religion.