Japanese language has three types of characters:
Kanji are based on Chinese characters. There are about 2000 of them in a standard Japanese vocabulary. The complex part of learning kanji is that each kanji has multiple readings known as kun-yomi and on-yomi. There may be as many as 3 to 10 readings for every kanji and you have to figure these out by the context in which they appear. This can get complex.
Hiragana are used for words that have no Kanji, suffixes and stems of verbs etc.. There are 46 basic Hiragana characters. These 46 characters represent the basic sounds of the Japanese language. They are a great place to start learning because if you can pronounce these 46 sounds you can pronounce most Japanese words correctly.
Katakana are used for words of foreign origin. There are also 46 basic Katakana that have the same pronunciations as Hiragana.
I don't want to go too deeply into Japanese language on this site because I am working on a new site about it. I will post the link when I am ready. In the meantime check out my really old site about Japanese: