Subpages not showing up

I was editing this site and in the process of doing so, made it so the subpages under “PEOPLE” no longer display on the right hand side. Before I made this error, clicking on “People” would bring you to Margaret S. Clark page, and on the side were links to “Graduate students” and “Research Assistants”. I would like to go back to that but can’t figure out how to get them back. I know that the pages still exist and are subpages under the links menu, but they do not display.

I am at a complete loss, any help would be appreciated. Thank you.