Typing in Japanese is very complex, because it requires knowledge of Hiragana, Katakana and Kanji, as well as Romanji. In Japan, many types of non-QWERTY keyboards are popular, but a Japanese keyboard is not required to type in Japanese characters. For an American typist, a combination of Romanized input and on-screen character selection is the easiet way to start typing in Japanese.
This video demonstrates how to set up Japanese on a Windows machine, and then demonstrates how the multiple input methods work. Narrated in English.