You can create a new page above, using a template as a starting point. The text you enter will be the URL ending, and you can rename the page later if you wish. Remember to categorize your article by adding the category's name, a colon (:), then the article's name.
Example: script:awesome-sauce, using the General template.
This will start you off creating a new page at http://smod.wikidot.com/script:awesome-sauce. You can swap templates at any time you want, by using the Initial content drop-down list.
While editing, you may want to check Wikidot's syntax reference and other help pages. Once saved, the article will be automatically added it to whatever category you specified.