SeaMonkey is an internet suite, consisting of a browser, e-mail client, HTML editor, address book and IRC chat.
(Past versions also included internet radio, AOL Instant Messenger, a JavaScript debugger, and a VOIP client, but all that is history.)

Now the purpose of this website is not so much to advertise the niceties of SeaMonkey in text, but to showcase its abilities by actually using its features.
So the first thing to do, if you're already watching this in SeaMonkey, is to activate the Website Navigation Bar to see the navigation controls.

View → Show/Hide → Website Navigation Bar → Show Only As Needed (or, Always)

If not, well, you may be able to guess some of the other pages' names and type those into the location bar of your browser.

Have fun!