If I properly understood your question... You need have Google Account first. Or create one and then join Google Analytics. Just follow some simple steps and add your site's URL and then place the code you get in your website before </body> and your read to go.
I have join analytic. snispsly is not my website but it is other website that offers adsense share revenue.
You can't use Google Analytics if it's not your site. You need to be able to put a chunk of code on the page