I have to admit, I was chuffed to bits with how easy it was to build these galleries. It's great to have Jomres to a point where adding things like these galleries is as simple and straightforward as this.
You don't NEED to be running the Quickstart to use these galleries. If you have a Jomres installation but you're using your own template then copy property_details.html into your own template's directory, in a sub directory called /html/com_jomres and put the gallery files in the same directory.
Install the Jomres Core plugin Bootstrap 5 Carousel in the Jomres Plugin Manager, then edit /html/com_jomres/property_details.html as described in this article and you should be good to go.