ok so, theres sps, small polyp stony. like acropora( looks like stony bushes) or montipora (most commonly in plating formations) these need very high lighting, like metal halides. then theres lps. large polyp stony. like torch coral, acans, frog spawn, hammer, the list goes on. just do some research on the wide range of sps and lps. lps generally need less lighting than sps. both are usually VERY colorful. they glow like a black light poster under actinics and blue led. looks really cool at night. and then theres softies. like leather coral, kenyan trees, and mushrooms. most are kind of a skin color. and these need mostly lower light and rely mostly on being fed phytoplankton. so i mean just type some of these terms on google and you should be able to find a site with a better explanation. ive only been in the hobby for about two months. you should catch on fairly quickly. and you will probably want to look into a protein skimmer. the most trouble ive had with this so far is picking livestock. wish i could explain things a little better, but it is 4 o clock in the morning. i hope you decide to go through with reef keeping, its a great hobby. good luck, and good night.