The dummy data buttons are at GeoDirectory > Settings > General > Dummy Data. Each post type has its own row with a data type dropdown and an Insert posts button.

You see Remove posts instead of Insert posts

When a post type already has dummy listings, its row shows Remove posts and the data type dropdown is locked. Remove the existing dummy data first, then you can insert a different set. Listings you added yourself do not count, and removing dummy data does not touch them.

The buttons are missing or do nothing

A JavaScript error on the settings page stops the buttons working, and the usual cause is another plugin or the theme. Open your browser console on that page to see the error, then turn plugins off one at a time to find which one causes it.

Some themes also load their own copy of Font Awesome, which can break icons and buttons both in wp-admin and on the frontend. Font Awesome Settings explains the options, and BuddyBoss users should add the BuddyBoss Compatibility Snippet.

Set a default location first

If you see a notice asking you to set a default location, do that first at GeoDirectory > Settings > General > Default Location. The dummy listings are placed around that location.

More about the options on this screen is in Settings Overview for General > Dummy Data and Add Dummy Data (Recommended).