Sorry for such a neewbie question.You don't have to be sorry for a newbee question, but you should be ashamed a bit for not checking our primer, although a clear message at the top of this area advises you to do so. "*** Welcome to the HTF", it says, "Please read this first ***".
OK, no hard feelings, of course, but in this post in our primer I tried to explain concisely about the things you asked.
Cees