* There: This is the word that indicates a place or location.
* Their: This is the possessive pronoun, meaning belonging to them.
* They're: This is a contraction of "they are."
Examples:
* There is a book on the table. (Indicates location)
* The children lost their toys. (Possessive pronoun)
* They're going to the park. (Contraction of "they are")
It's easy to get these spellings confused, so paying attention to the context of the sentence is essential!