This fish is not one of the easier tetras to breed. Tetras, as whole are not easy, at least for me, and never have been. The water parameters, to me, seem hard to replicate, especially here in the Great Lakes area. Water needs to just a hair to the alkaline side but also needs to be very soft. Using RO water and "building" your water has come into favor in recent years.
Some who have bred this fish have done so with a by placing a single pair in a tank. I bred mine in a community tank, purely by accident. Some have also kept species tanks. I would suggest using marbles as a substrate to allow protection of the eggs. The parents may cannibalize the eggs, but they could be removed after the spawning cycle is complete. Another option would be to use java moss, najas, or some other dense, low growing plant to protect the young and the eggs.
The fry are very, very small at hatching and foods should be chosen that takes that into consideration. They can be fed a liquid egg layer fry foods, available at most lfs's or infusoria(green water) until they are a week or two old. As they get bigger, baby brine shrimp and microworms may be introduced.
Like I said, this is not a "gimme" fish to breed like many. It can be frustrating. It always seems like any fish that I am adamant about breeding gives me the most frustration. Be patient and provide them the necessary conditions. If it's meant to happen, it will. But, it will be on their timetable, not yours.