hey congradulations on your new fish :)
here is a betta care link to check out
what size is your tank? it should be at least 2.5 gallons with a Heater (thats a must) and filters make it eaisier. If you use tap water you have to add conditioner or else your betta will die.
male bettas (unless a plaket betta) would have big, colerful fins that he stickes up and when exited males flare their gills out. the females tend to be smaller, somtimes less colorful and have much shorter fins