I'm still an Application Express beginner -- I'm used to web development that is closer to the HTML. While I am getting used to Apex's Regions and Templates sometimes you just need to build some HTML on your own. I have found some Apex helper functions that can help you whip up an anonymous PL/SQL block that can generate this.
In Apex, add a "PL/SQL" region. You will get a blank textbox where you can enter some PL/SQL code. If you have the Demo application installed you can try this out: