Before you do anything else, stop and think.
Do you have 3 tanks, one for the male and one for the female to condition them in and one for spawning and raising the fry.
Do you have a lot, and I mean a lot, of small tanks/jars to separate the male fry, and the means to heat them all.
Do you have someone who will buy all those baby bettas from you, remembering that shops will only take males once they have grown their fins, which takes several months.
Do you have a male and female of a tail type/colour pattern that shops will want to buy. There is no point breeding veiltails as you won't be able to sell them.
Breeding bettas is not a simple task and you need to do a lot of research before embarking on this. In basic terms, you need to condition both fish in separate tanks. Then put them into the spawning tank with the female inside a container where the male can see her but can't reach her. Once the male starts to build a bubble nest and the female shows signs that she will accept him let the female out of her container being ready to remove her straight away if the male (or even the female) becomes too aggressive. As soon as spawning is over, the female needs to be removed and nursed back to health as betta mating is violent. The male remains with the eggs until the fry become free swimming then he too must be removed before he eats them. Finally, you have to feed and care for the fry until they reach a saleable size. Female fry can remain in the spawning/nursery tank but males have to be housed individually once they start to fight.
This is not something to be undertaken just on a whim.