I live in a condo and the air conditioning has been turned off for the winter. But it is warm and going to get hot in the next few days! I have heard one can use water and the central unit fan to cool down the place - but I have no idea how this works. Anyone know how to make things cooler? Thank you.

Do you not have a control to turn the ac back on?
You could set the tstat to fan/fan only to help mose existing air around in your condo, better than nothing