As far as i am aware you breed them in a similar way to other barbs or danio's- create a perfect environment for them to encourage them to spawn, and then remove the adult shoal after spawning to prevent them from eating their eggs or fry afterwards. However, i'm not so sure on how successful or easy breeding tiger barbs is in aquariums.
Taken from;
http/badmanstropicalfish.com/profiles/profile20.html
"Male tiger Barbs are slimmer and more colorful than the females. They breed similar to other Barb species. The breeding tank should have a thin layer or no substrate and a few leafy plants and be as large as possible. Condition the spawners with the best food possible for a few days before transferring them to the breeding tank. They usually will spawn the morning after being introduced to the tank, a partial water change can also induce spawning. The female is the more active partner and will lead in the courtship. After chasing and false matings the pair will spawn in the plants, with the partners coming alongside each other and the male twisting around the female. The eggs are scattered among the plants and they can be quite large in number. Tigers, like most Barbs are spawn eaters and should be removed from the tank right after mating. The transparent eggs will hatch in about 24 hours at a temperature of 75º and the small young must be fed the finest of food like Brine shrimp Nauplii, once a little growth has taken place they are fairly easy to raise."
Breeding fish like tiger barbs is not half as near as certain as breeding livebearing fish like platys and guppys, so you may have to wait a while before your tiger barbs even start to spawn in the tank, let alone see any fry hatch out successfully. And if danio fry are anything to go by in my experience, they are absolutely tiny- its very easy to miss the fry since they lack any particular colour and are very small.
Fry tanks also need a lot of maintanence, mostly due to the fact that feeding small fry can be quite a messy buisness and that small fry need pristine water quality conditions to grow well and survive.
Have you bred any fish before?