Hi sabilfikri

First of all, welcome to the insanity that is WOW.

The other guys have given you some good advice so I'll just add a couple of things you may not be aware of that will help you enjoy your stay in Azeroth (and Beyond).

There are a couple of excellent websites, but I think the best collection of everything you wanted to know about WOW is at http://www.wowwiki.com

I suggest you start here: http://www.wowwiki.com/Newbie_Guide

This will help you along much better than random advice from strangers in general chat.