The old [gd_listing_slider] shortcode was part of GeoDirectory v1 and no longer exists, which is why it shows as plain text on the page. In current versions you make a listings slider with the GD > Listings widget and its carousel option.

Set up the slider

1. Add the GD > Listings block, widget or shortcode to your page. It works in the block editor, WPBakery, Elementor and other builders.
2. Choose the post type and, if you like, the categories to show.
3. To show only featured listings, tick Show featured only? in the Filters settings.
4. Set Posts to show to the total number of listings in the slider.
5. In the Carousel settings, set With Carousel to Yes. You can also turn on the previous/next controls and indicators, and set the interval and autoplay.
6. Use Layout to choose how many listings are visible on each slide.

The same slider as a shortcode:

[gd_listings post_type="gd_place" category="3" post_limit="5" show_featured_only="1" with_carousel="1" with_controls="1" with_indicators="1"]

The carousel options are part of the current (AUI) design style, which is the default.

Images of a single listing

To make a slideshow of one listing’s photos, use GD > Post Images with its type set to slider.

All the GD > Listings settings are explained in GD > Listings.