anyone know how to do it? any tips on it? i figure i should get into culturing them for my many fowlr tanks and future cuttles

Thanks

It takes a lot of space and a lot of work. A general rule is you need 4 times the water volume for culturing food as for the animals you are feeding.

wow that sucks so if i have 400 something total gallons ile have to times that by 4?

Something like that. It varies some depending on the food animal you'll be raising. You need volume of feeder animals, and you need all different stages of the life cycle available in order to have a consistent available food supply of the various sizes you'll need.
I've looked into a few times, but have always come away with the decision that culturing live food for cephs is pretty much a full time job on its own, which is one of the reasons cultured foods are expensive as compared to wild collected.

You live on the island, maybe you can collect some yourself or find a bait shop nearby.

i have thought about collecting but i dont if feeding tropical fish/cephs shrimp from around here would have any affect on them.

Doubtful it would have any ill effects as long as they are collected from a clean place.