Have you got food for the babies?
The following link has information about making live food for baby fish. You should try to get the food ready before you breed the fish so the babies have something to eat when they hatch.
http://www.fishforums.net/threads/back-to-basics-when-breeding-fish.448304/
Betta fry are small and need green water or infusoria. If you can't get these you can hard boil an egg. Remove the shell and white part. Push the yellow yolk through a handkerchief into a small container of dechlorinated water. Put the lid on the container and shake it up, then use an eye dropper to suck some of the egg yolk solution out and put it in the tank with the babies. Do this 3-5 times per day for the first 2 weeks then start adding newly hatched brineshrimp.
Boil another egg each day and make a new solution each day. Do regular partial water changes on the fry tank or have a small air operated sponge filter in it to keep the water clean. The egg yolk can cause ammonia levels to go up and without water changes or a filter the fry will die from polluted water.
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Make sure you feed the adults fish well for 2-4 weeks before breeding. I use to feed my breeding stock 3-5 times per day with dry, frozen (but defrosted) and live foods. Do big water changes each day or every couple of days to compensate for the extra food going into the tank. Don't breed the fish until they have been well fed for at least 2 weeks and preferably 4 weeks.
The male will build his bubblenest and if the male can see the female he will start displaying to her. When you see him showing off to her you can release her from the trap and monitor them. If the male bashes the female get her out immediately, otherwise leave them together for a day or so. If the tank is big enough and has lots of plants in the female can sometimes stay with the male after breeding, but most people remove the female after breeding and let the male take care of the eggs and fry.