In order to reserve a space, you will need to check for openings on recreation.gov and then check into the visitors' building. There are showers, bathrooms, and water available on site. There is also a campground host present and a few trails within the park. If you want to go to the beach, Front Beach of Ocean Springs is only a 15 minute drive and it is very clean and uncrowded.
Campground is first-come, first-serve, but when we went there were plenty of spaces available. It was quiet and peaceful with lots of space in between each group. There is no campground host or check-in service. There is a toilet and sink, but I would bring your own toilet paper, handsoap/sanitizer, etc. We only had time to briefly walk one of the trails around the lake but it was very nice.