LifterLMS modified my theme

Good evening,
I installed LifterLMS and it has modified my theme. I now have a sidebar on my pages where I don’t want or need a sidebar. I am using the responsive theme, and I’ve looked every where I can think of in the customizer and can figure out how to get rid of it. How can I undo these changes and get rid of this sidebar?

The page I need help with: [log in to see the link]