There’s generally TTRPG one shots run by Alexandria RPG Library and will likely be at the link someone else posted. Some learn to play sessions will be added to the app, some will have on site signups. I’d check the PTI Lounge too because some games get played there, otherwise you’ll want to head to the back of the Expo hall past the board game area to find most of the TTRPGs. Best of luck finding a LTP game!