How will I know when it has taken effect?
And given that the primary domain on wordpress is already set to paket-paket.com does that mean It will work automatically or do I need to remove it and add it again?
Good news: it's working right now, and I'm able to see your domain when viewing your blog. :-)
Can you clear your browser cache and flush your DNS cache? You should be able to see it as well.
Let me know how that works for you.