A "thread" can be called a topic or topic start if you start a thread other people can answer in your thread and the posts they make in this thread can all be seen in that particular thread only... so threads are needed to keep a certain order... hope I didn't explain it to bad
:m-bata:
You think what you want to talk about let's say you like to chat about Cars look if there isn't a thread with that topic already there if not procceed... a "cars" thread would fit into General Discussion area go there and simply scoll down you see a button "New Thread" hit that and you can type down a name for the thread if it's cars you should name it "Talking about cars..." or something so everyone knows before opening the thread what it's about.
While creating the thread you can type down the 1st post content to open the discussion.... hope that helps.
If you need more advise just ask.
:)