How to create a page within a templated website without the frame

This is my website:

https://www.blackstone.edu

If you click on any of the secondary pages, you’ll see that the yellow “enroll now” and “request info” buttons on the left-hand side, as well. I’m kind of self-taught on WordPress so if my vocab is off I apologize.

What I want to know is basically how do I create a new page without the left-hand column with the buttons on it? It’s part of the menu or framework of the site, obviously, so I’m not sure where to go to access that and make edits without changing the rest of the site. Thank you.