There, they're, and their: they sound the same but have different meanings and keeping them straight can be very tricky.
We'll start with there. It has the word here in it, which can help remind us that this particular word is often about location:
There it is.
Put it there.
Stay there.
We'll be there soon.
It's about location in the more abstract sense too:
There you go.
There is where we disagree.
Friends who are always there for you.
It's also the one to use as the first word in sentences that have the subject after the verb:
There goes the bus.
And it's the one used with is and are at the beginning of sentences and questions:
There are plenty available.
Is there a hotel in the town?
The other two are trickier because they both have the idea of the plural in them. Both are connected to the idea of "them."
They're means "they are":
They're (=they are) funny people.
They're (=they are) the cutest puppies ever.
It can be used of non-living things too:
They're (=they are) both really good books.
They're (=they are) two of our biggest problems.
The last of this trio, their, is the possessive form of they, so it has to do with what belongs to, relates to, or is made or done by certain people, animals, or things:
It's their house.
We're their neighbors.
The trees are losing their leaves.
And there you go. They're not an easy group of words, but with practice we know you can master their distinctions.