I think I your question could be 2 questions…

1) How do I install it?
Right here https://www.google.com/analytics/home/
Just sign up for a free account.

2) How do I Use it?

• First determine the type of site. Eg. Lead Gen-Ecom- Brandlift- Social.
• Second Block IPs that should not count as visits
• Third determine KPIs (key performance Indicators)
• Fourth create of goal conversion funnel

If you are new to Google Analytics and really want to milk it for all its worth develop the mindset here http://www.kaushik.net/avinash/.

If you already have a good idea of how the net works you will have a distinct advantage over others learning.

The final step is where all the fun starts. Taking action after you have collected enough data .

The most powerful ROI booster on the net, especially if you also use AdWords.

Enjoy the ride

You install a simple tag into your website like at the bottom

<script type="text/javascript">
document.write( ‘<scr’+'ipt type="text/javascript" src="’ );
if( document.location.toString().indexOf( ‘https://’ ) != -1 ) {
document.write( ‘https://ssl’ );
} else {
document.write( ‘http://www’ );
}
document.write( ‘.google-analytics.com/urchin.js"><\/scr’+'ipt>’ );
</script>

It’s probably less then this since this is an older code I used, lol.

Anyway it scans who goes onto your site and directly places it into your free analytics account listing where people come from, such as if they come to your site from a link. And other useful stuff such as where they quit your site, or which pages they viewed most etc.

Webalyzer is almost 30x as infotic so I personally use that..