yumi_nakata wrote:

QUOTE:
Which differences among kanji,hiragana n katakana? Which one is used popular most? Sr,I've only a few things about japanese.

Kanji is basically an import of Chinese characters into the Japanese writing system. Whenever possible, you write in Kanji.

Hiragana are Japanese characters that are used phonetically. Anything that can't be written in Kanji is written in Hiragana. And finally, if you come across a foreign word (Ex: Words that are not of east asian origin), it is written in Katakana. Don't worry about which is more popular or not, you will need to know all 3 if you want to be able to read in Japanese.

QUOTE:
Would some one possibly be willing to explain how to properly form a sentence? I know a lot of words and I know how to properly pronounce them. But I have no idea how to make a sentence. -.-'

It really depends on what you're trying to say. And like with any language, you need a minimum of a noun and verb to make a sentence