How to show similar/nearby properties in single property page.

There is a widget area (sidebar) in WPL named "Property Show Bottom" for showing any widgets at the bottom of a single property page. You can assign a WPL Carousel widget to this position and show similar listings by enabling the "Only Similars" feature of the WPL Carousel widget.

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Also, you can show nearby listings by enabling the "Include Radius" feature and set its values.