Katakana is used for foreign words, like English words, like Mariokart, which becomes: "マリオカート" ma ri o ka a to I might make a kanji guide for the basic ones.
This is another one of the Japanese alphabets. Most letter can have a 点々 (tenten) added, which changes the sound. For example: (か) is "ka", and (が) is "ga". 点々 can be added to; - k (becomes g) - s (becomes z) - t (becomes d) - h (becomes b, which then can become p) I am studying Japanese at my school. 私は学校に日本語を勉強します。