I just downloaded WAMP 64 bit. Successfully installed. Everything went fine.
Problem is, I don't know where to go.
Where do I put my codes?

Online resources I have read says just create a directory in the root folder or something.
Does that mean create a folder in the "www" folder???
I did that. And yes, it created a folder link in the localhost page. But when I clicked that link, it displays nothing.

Can somebody shed some light here?

the root of your web server is the "www" directory. To create a "front page" of your website you would create an index page. If you're using PHP it would be index.php

After that you can create directories to structure and organize the files for your website like images, css, js, and so on.

And that is just the start! :-) Remember, PHP is an object-oriented language. If you approach it that way (C++ for web sites), then you will do well. If not, then I have a gazillion examples of failed PHP projects that forgot that maxim!

How do I create an index file? What codes do I include in that file? (@pixelsoul)

Judging by your current skill set, I would focus on your standard HTML, CSS, and JavaScript right now, and then then focus on PHP at a later time. Don't take that in the wrong way, I love PHP, but you really should get the basics in first.

There are a number of great resources out there for learning basic building blocks of a website. Here are some examples:

You can try these, and there is a bunch more out there you can find. After you've started working on some of the lessons/tutorials on these sites, and you have questions about what you have done, or you've run into some problems, come back here and we can help answer those questions.

Right. I just started PHP literally days ago.
Looks like I really have to back up a bit.
But do I have to do javascript? Is it really necessary to learn Javascript first before PHP?

I think JavaScript is an important thing to know in web development, but it's not mandatory to know for PHP development. I would recommend picking it up in the future though.