You're is a contraction. It means "you are."
Use you're in your writing only when you can substitute the words "you are."
Example of you're in a sentence
Your is a possessive pronoun, like my, his, her, their, and our.
It means "belonging to you."
Use your in your writing only when you mean to show ownership.
Example of your in a sentence
Link to exercise on you're / your.