Creating a new article on Wikivex is pretty simple. Just change the adress on your browser's URL bar. In an exemple, you are at this moment visiting the page http://vexillium.wikicities.com/wiki/Wikivex: Help , where Wikivex: Help is the name of this article, right? So, what if you want to create an article on, say, the History of Cruisana? Simply acess http://vexillium.wikicities.com/wiki/History of Cruisana! The new article will be created and you'll be prompted to its edit window.
To put it in another way: If you're already browsing Wikivex, you'll just need to take a look on the page's adress, delete the words after the last slash (which are the name of the page you're currently viewing) and enter there the name of the new article.
Alternativelly, you can visit one of the many red links arround Wikivex. While blue links will take you to already-existing articles, red links are pages with currently no text.
Another note when naming your new article: Wikivex is case-sensitive. That is, it will treat an article named Article differently than one named ArtICLE or ARTicle. Have that in mind.