This is an instance when having CC shouldn't matter. Things have remained unchanged for Rotobrush: if you're trying to use it intuitively, you'll fail. You need to look at documentation and tutorials. You'll find them when you nose around here:
...and if you're new to AE, you'll need to spend some quality time looking that page over.
The tutorial I am watching on YouTube is doing the exact thing I am trying to achieve. If there are areas he doesn't want he can erase them. For some reason it won't let me on mine.
Upload a screen capture of the issue that you're having so that we can better understand what you're trying to do and what isn't working.