When do you use you’re?
You’re is a contraction of you are. It has no other uses. This is a 100% rule. If you cannot expand it to you are in your sentence, then it is wrong.
When do you use your?
The word your sits before another word (usually a noun or a pronoun) to show that it belongs to “you” (e.g., your car, your arm), is of “you” (e.g., your picture, your photograph) or is related to “you” (e.g., your uncle).
Your is a possessive adjective. (Other possessive adjectives aremy, your, his, her, its, our, and their.)