[Plugin: embed-javascript] Adding JavaScript to each page

I am new to this whole JavaScript thing. It is so confusing. I was told that I need to add JavaScript to each page that I want to track with Real Time Statistics. GoDaddy gave me the script and it says that it needs to be copied and pasted into each page just before </body> tag at the bottom of the HTML page. Can someone please explain to me what the means? Where do I post the JavaScript to get the real time statistics that I want for each page?

http://ww.wp.xz.cn/extend/plugins/embed-javascript/