If you don't have a water conditioner to treat your water, you'll have to let your water stand for 24 hours before adding your fish in. this gets rid of cholrine and other harmful chemicals that can kill your fish.
To put the fish in, you first put the bag (or cup or whatever he came in) in the bowl and let it float around for about half an hour. This is so that the betta gets used to the different water tempuratures. if you dump him into the water right away and there's a big difference between the two, I think they can go into shock.
I'm assuming that since you're in Hawaii it's nice and warm where you live, so I don't think a heater would be an issue.