I've just made my first camping reservation at p.v. how do I locate the ranger station to ask questions about my stay?

You will come across the station as you enter the park

Ranger Station at entrance

As you enter the park there are public bathrooms on the right, then there is a one lane bridge, after crossing bridge the park office is on the right. If no one is there they use the honor system just go to your site, and also you may have to call Reeds Gap state park, that's where the people who run the parks have there main office.