So far, the tutorials have covered how to add a page with a tab, but I suspect you will want to more than one page and control tab order. To do that:
Follow the instructions on http://ets.tlt.psu.edu/twt/node/167 for creating a "Teaching Philosophy" page or http://kb.its.psu.edu/psu-all/hd/faq-s-about-using-the-professional-webs.... Don't forget to include to @topnav in the Tags field.
When you add multiple pages, you may find that the tab for the new page does not appear on older pages. To fix that, you need to Publish all pages.
You will see a pop-up window showing the progress of the publishing process.
By default, a portfolio template includes "Home", "Blog", "About" and "Contact". To hide these pages/tabs, do the following:
The tab order is set (from left to right) for Home, then your portfolio pages, then Blog/About/Contact. New tabs are added immediately to the left of the Home tab and before the last three default tabs.
The order of the new tabs is set by original publication date with the earliest date to the right and the latest date to the left. If the tabs are not in the ordered desired then, adjust the publication dates of each page to an appropriate sequence.
In http://www.personal.psu.edu/ejp10/blogs/portfolio_t/, the leftmost tab after "Home" is Philosopy" and the right most is "Links". Between them are "Classroom", "Communicate", "Innovate", "Media".
To achieve the order I want I pick the current month (e.g. October) and assign dates as follows:
It's not hard, but it does require thinking about which pages you have and how you want them ordered.