I never bred bettas before, but I do know exactly how to breed them.
Here are the requirements:
-Condition the pair with nutritious foods, such as live foods.
-Make sure the pair fits--The male won't attack her.
-Give the male a quiet, stable spot to buil hid bubblenest.
-Remove the female after breeding is complieted.
-Feed the newborn fry with small livefoods such as infusoria followed by newly hatched brine shrimp.
-Let the male guard the eggs and fry for about a week before removing him.
-Let the pair rest for about a month before trying it again.
Hope all these helps and I wish you success!
Unlimitedfishboy