Okay, very simple.
Soft corals include leathers, pox pox exinia, etc. (poor spelling i know) Very easy coral, fast growers.
There are zoanthids and palythoas: Soft corals, actually classified as "matting anemones" They have radially identical polpys that open when all is good and close when something off, easy coral, grows almost anywhere.
SPS: small polyp stony corals, multiple example in above posts.
SPS include plating coral, encrusting coral, branching coral, etc. Extremely small polyps, almost unnoticable unless looking for them.
LPS: Large polyp stony corals, again, multiple examples in the above posts.
These include, favias, CANDY CANES, acans, lobos, chalices, etc. they have large feeding tentacles and you can spot feed them mysis shrimp and they will eat it.
Thank you SWF.com without you guys I wouldn't know any of this and my tank would be a failure, thanks to you guys i have done DIY builds for tanks, our 95g is doing good (dang cyano algea won't go away)
I also have a 3g pico that is my display picture.