If you find a gallery, tap the wall and listen for a rustling sound. Carpenter ants do not eat wood like termites. They nest in it. As a result, their galleries will be completely spotless and look like somebody went at it with a flexible drill bit. They even carry away the sawdust. By contrast, termites will leave messy galleries full of dirt. This makes carpenter ants easier to spot. They will leave little piles of sawdust at the entrance to their nest. If you find one, you need a gas or vapor product to ice them. Drill a small hole in the wall a few feet up, insert crevice tool, and toast 'em. Repeat on the other sides of the studs. Do NOT do this sort of thing if you find a group of them running around the house. Use bait for that. Only use a quick-kill product on the colony itself or you'll create new ones. Use plenty of poison on the colony or it will just split off and make ten more. Let no ant stand alive, and leave no fleck of wood on another. Complete annihilation is the only option. I recommend flying a red flag and playing "El Deguello" before the assault. I know I'm getting silly here, but I really mean it. Not one ant left alive. Any forager can, and will, create a new colony if the main colony is threatened.
If you found just a few of the larger ants in the house, I wouldn't worry too much. They're probably just foragers. I would, as a precaution, pick up a couple of gel baits at the local home improvement store. As cfabe said, the gel baits work wonders. Even if you've only got five ants in the house, their chowing down on a gel can kill an outdoor colony 50 yards away. You can also use any barrier product (gel, spray, granules) to create a poisonus barrier around the house.