- You don't need the "configuration variables" section. Check out some other examples of scripts here, or view the source of this page to see the predefined variables you can use.
- You need a line of code in your own /vector.js or whichever skin you use that tells MW to load your script. (addOnloadHook(yourfunction);)
- If you want to have a page that the user will use to define what goes in this menu, you'll need to use the API to grab the contents of that page.
This short script has some examples of what you're looking for.