How to track the subdomains?

How can be subdomains of one site be tracked and be agreggated?
I have red instruction here: but there in exampls javascript code should look like this

_paq.push(['setTrackerUrl', u+'piwik.php']);
_paq.push(['setCookieDomain', '*']); // Same cookie as:,,, ...

and my Piwik gives me this:

var pkBaseURL = (("https:" == document.location.protocol) ? "https://domain/analytics/" : "http://domain/analytics/");
document.write(unescape("%3Cscript src='" + pkBaseURL + "piwik.js' type='text/javascript'%3E%3C/script%3E"));
</script><script type="text/javascript">
try {
var piwikTracker = Piwik.getTracker(pkBaseURL + "piwik.php", 75);

so I don’t know how to implement those instractions.
Please help me with this

First, update the code with the latest code found in SETTINGS > Tracking code

then you should be able to follow the instructions