One of the most common meanings of there is “the opposite of here” – thus denoting a location. The expression even contains the word here in it, which might be useful when trying to distinguish it from the other two. In this sense, there is used as an adverb:
She asked me to go (where?) there and bring her the thing she needed.
Stay (where?) there and don’t move.
The expression can also denote location in a more abstract sense:
Your parents will always be there for you.
Another frequent usage of there is as a pronoun, with a function of introducing a word or a clause:
There is something peculiar going on in that place.
There are 20 pieces of chocolate in the box.