Papia and his fellow tour guides are expected to know a wealth of information about the national park from biology to geology, and even history, which can be rather daunting their first few weeks on the job.
"It's very overwhelming at first," he said.
Tour guides are given a general outline in which to follow while leading tours, but after gaining some experience they are allowed to interject points of information from research they may have done.
"So, you kind of do it step-by-step, even though it seems like something you would have to learn all at once," Papia said.
"You can focus on the things that you are interested in the most and then start picking up on other things," said Ana Casilla, who is also a tour guide.
Papia and Casilla have been tour guides at Mammoth Cave for about a year and both admit to having carried cheat sheets with them while leading tours.
"Sometimes you have to (carry a cheat sheet), if you are in a new part of the cave, just to remind yourself, 'Oh, this is what I wanted to touch on,'" Papia said.
The tour guides must be prepared to answer visitors' questions as best they can.
"You never know who is on your tour," Papia said, adding there could be geologists or archeologists taking the tours.
Learning everything there is to know about Mammoth Cave is an on-going process, even for those who have worked at Mammoth Cave for several years.
"There is so much in this park to know and to be able to respond to because it focuses on history, biology, geology and everything," said William Thomason, who has been a tour guide at Mammoth Cave for five years. "It is a long-term investment because it takes several years before anyone feels strong about multiple aspects."
One of the scariest things for new tour guides is learning to speak in front of large groups, said Johnny Merideth, who has been a tour guide at Mammoth Cave for 16 years.
"Probably, the most unnerving thing, if you've never done it, is to stand in front of 120 people and have them to look at you as a subject matter expert on everything," he said. "They don't know that it's (your) first day giving a tour in the cave ever. (You're) wearing the green and the gray and the hat and (you) must know everything about the place."
The first two weeks for the new tour guides is spent learning rules, policies and procedures, such as what should they do if there is a lost visitor or if someone needs to be extracted. After the first two weeks has past, new tour guides then tag along on tours or "trail" veteran tour guides to gain on-the-job training.
"The trailing, I think, helps build confidence because when you're trailing a tour, you really get to know the cave itself," said Chuck DeCroix, who has been with Mammoth Cave for more than 15 years. "You learn where the light switches are and what passages to take. As you get to the front for the first time . , there are a lot of passageways to take and it can get kind of intimidating your first time, especially on the longer tours."
As the tour guides learn the information they need to share with visitors, they begin to spend more time inside the cave leading the tours.
"My own personal experience . is that when you're brand new and you are leading the first week of cave tours the tendency is that you always get out of the cave early," DeCroix said. "In fact, sometimes it is 10 to 15 minutes or even 30 minutes early because you're knowledge of the cave; you have the basics down, but when people start asking these detailed questions, maybe you can't elaborate and you haven't perfected your questioning techniques and the timing."
Just the opposite happens when tour guides become comfortable with the tours and with answering visitors' questions.
"The next thing you know you're coming out of the cave late because you want to tell them everything," he said.
The newest tour guides to Mammoth Cave arrive on June 5.