Here is how I breed bettas. First, when your ready to go your females vent should have a white dot covering it. Place your male in a plastic sweater box and provide floating material, a styro cup cut in half lengthwise, a circle cut from a trash bag or plastice lid, what ever. Once he blows a few bubbles in te float stuff place the female in a mason jar filled about an inch higher than the water in the sweater box and place it in the sweater box. The male should blow an extensive nest while trying to attack the female. Leave her in the jar at least two days. Take the female out of the jar and replace the water placing the jar in the back corner of the sweater box. Make sure she can just barly fit behind it to hide. Once you observe the spawning or the male is busy with eggs get the female out. Once the eggs hatch out goes the male. Run some super lite air and feed green water. Feed about 1/2 cup twice daily for a week. Move fry to a 10gal after that and use a sponge filter.
Green water: Siphon your tanks and get as much fish waste as possible. Place it two mason jars with aquarium water. Put it out in the sun and in a day or so, green water.