"your" is saying that the person you are talking to owns something "you're" is describing something about the person you are speaking to to "there" is saying the location of something or describing a location "their" is possessive, similar to "your", its used when a group of people, a nonbinary person, someone who's gender is being concealed, or someone who's gender is unknown to you, owns something, and "they're" is when describing group of people, a nonbinary person, someone who's gender is being concealed, or someone who's gender is unknown to you