Opengrave, I’d love to help you out, but I’ve never kept a Betta so I don’t have any ideas on what they like to eat. Try Rasa’s suggestion.
There is a point to my post however. You asked how often to feed your fish and while most things I’ve read say to feed your fish small amounts once or twice a day, I had a fish-store employee once give me different advice that I’ve followed for about 10 years now.
I only feed my fish once every other day. Sometimes I’ll even skip two days between feedings.
I wouldn’t necessarily recommend this approach, even though I’ve had a lot of success with it. The real message is that it is much safer to underfeed your fish than to overfeed them. You can kill them by overfeeding (or at least foul the water quickly), but I’ve seen no effect from underfeeding.
YMMV.