Could you please clarify if you’ve customized the template? By default, there should be a sidebar present. For example, on the demo site Real Estate – ListingHive, there’s a left sidebar by default with the filter form and widgets (which can be added in the Listings area in Appearance > Customize, they’ll appear below the form).
It’s possible that you’ve overridden the Listings page in HivePress > Templates, as the default layout definitely includes a left sidebar (and this layout is independent of the theme, unless of course the theme you’re using explicitly customizes HivePress layouts).
I definitely have a template set up for that page because I need the layout in a certain way and have some control over the layout. In fact, I haven’t finished modifying the template yet.
So is it possible to add the sidebar by editing the template?
Another possibility I was thinking about is having the listing display as a page.
Maybe you could advise me on how to best achieve this.
Could you please clarify what you mean by “the listing displays as a page”? As all listings have their own dedicated page, once you select it from the listings page, it will open.