World of Warcraft Download Help?

I am downloading World of Warcraft from the internet, so I don't have the discs. When it first started, it took about 10 minutes to open the first launcher. Then it took like 5 hours to download the newest chapter, or whatever they are called.. after it was done, a second one popped up called world of warcraft cataclysm, it is almost halfway done. Is there any more like this that I have to download? or is this the last part. Please explain in detail so I know whats going on and how long this is going to take!