not2easy - 5:05 pm on Jan 23, 2013 (gmt 0)
Firefox has an addon "Live HTTP Headers" that you can invoke to see what files are being called for a request and from where. It is not a simple to understand tool for a noob, but it is simple to use and with some trials you can learn to understand what it is telling you.
My suggestion would be to install the addon, then in FF go to Tools and click on Live HTTP Headers. A new little window opens up and as soon as you enter an URL (or click on a bookmark) it begins recording the server's responses along with listing the files that are being requested and lines showing properties of those files or responses. If you start with your own pages you can go down the list and probably recognize the files being loaded to display the page. To really be able to study the list you will need to click to "Save All" and give the file a .txt extension so you can look at it in notepad or any text editor. It IS a learning process. When you feel comfortable using the tool, then it becomes useful to follow the other instructions given in your post. Others may have better information, I use it occasionally but not every day.
There are other tools available, one is called fiddler which I believe is free.