Well, if you want to keep them in the same tank, just add a lot of fluffy or leafy plants. tetras are egg scatterers, and, unless there is a lot of cover for the eggs, they will eat every last one.
If you want to move them to an egg-laying tank, you can just take a 10-gal and fill it with an inch of marbles and cover the marbles with 6 inches of water, when the fish start laying, put them in the marble tank so when they lay the eggs, they will float down between the marbles and the parents cant eat them.
Im no expert being as ive only ever bred them once, so, I suggest googling how to breed them. That always helps me.