Help needed with JQuery and tabs

Hello,
Well... there is a function which switches between the tabs on click and I suppose one of the tabs is chosen by default.

$(document).ready(function() {
        var tabContainers = $('div.tabsdes > div');
        tabContainers.hide().filter(':first').show();
        $('div.navigation div.menu a').click(function () {
                tabContainers.hide();
                tabContainers.filter(this.hash).show();
                $('div.navigation div.menu a').removeClass('selected');
                $(this).addClass('selected');
                return false;
        }).filter(':first').click();
});

Code (markup):

That is the code from jquery.tabs.js. I see that here the first tab is chosen to open when the page is load - " tabContainers.hide().filter(':first').show();". However, I want to change it on a different tab, for example the third. When i change ":first" to ":third" it doesnt work... The fifth tab is activated where i load tha page.

Can you please help me. Where I'm wrong?