I'm not trying to be sarcastic here, but have you considered taking it back to whomever you bought it from, and asking them what the remote is for?
I realize that this is too logical for some folks, but it might be the cheapest way of finding out.
If that person has vanished from the face of the Earth, you could take to the dealer and at least ask them if the car HAS remote control locks.
I doubt they would charge you for that.
Just be careful NOT to buy a remote from the dealership.
Unless, of course, you like being robbed, blind. lol
Seriously, you won't believe what a dealer gets for a new remote key fob, and programming.
The charges border on illegal price gouging.
They do have the right to charge whatever they want, and you have the right to avoid being over-charged.
If it's only a matter of a replacement keyfob, then you might investigate
ebay for one instead.