[Michael Steinberg]"I want to add what I call a "banner" to a video. This is a text box that will be placed at the bottom of the screen like they do in news casts."
They are called Lower Thirds in the broadcast industry (I tell you this so that you have good keywords for your Google searches) and they are very easy to make.
Use the Generated Media plug-in to create the bar. The Solid Color generator or Gradient generator work nicely for this. Movie Studio doesn't have a Mask tool like Vegas Pro, so you can't mask them to get them to only cover the lower third of the screen so you'll need to resize it with Pan/Crop.
Then just place your text on a track above and you have a lower third. Of course you can get fancy and use multiple layers of generated media. It's a lot easier with Vegas Pro because the mask tool allows you to quickly make irregular shapes. You could also make these with any graphics program and save them as PNG files with alpha transparency.
If you upgrade to Movie Studio Platinum 12 or greater, you can buy Title Strips from VASST. These are premade lower thirds with titles that do all of the hard work for you but they require Movie Studio 12 or 13 or Vegas Pro 11 or greater.