Thank you Kor.
However, I am not looking to have the “add listing” link appear in the main menu. I want it to appear in the dashboard for Authors. This function works fine on mobile, but not on desktop as I showed in my images above. For some reason, it is hidden on desktop.
As for the sidebars, enabling or disabling them does not seem to do anything. The “add listing” function doesn’t work on desktop in the dashboard with or without the sidebars.