If you want to add Author widget , Bids Offer Map View Widget, or any other Widget on Listings details page please go to Appearance > Widget > Add here you desire Widget and Save it. As in attached image.
Then go to Pages > Our Listings > and select here “right sidebar” in page layout and select “Listings Single” in Chose a Sidebar > Save it. As in attached image.
Your Widgets look like this on Front End.
Hope this Article will help you.