the different from "watshi wa", "watashi no", "watashi ni"?Give me explanation and example :)

Question

Answer

私は：わたしは：watashi wa 
you can use this word as a subject of the sentence.
ex: わたしは　学生　です。 I am a student.

私の：わたしの：watashi no
you can use this word as a word  "～ 's"( possessive case）.
ex: それは　わたしの　ボールです。Its my ball.

私に：わたしに：watashi ni
you can use this word as an object of the sentence.
ex: あなたは　私に　本を　くれた。 You gave me a book. / You gave a book to me.