The Theme Options (link is located at the bottom left of the wp-admin Dashboard) has all your settings for controlling the homepage Slideshow.
You will surely want some of your property Listings to show up in the Slideshow on the home page. The basic way to do this is to set the Category that the slideshow will use. To do this, go to Theme Options, and then in the Slideshow section, choose a “Category used for Slideshow” from the dropdown. You can choose your parent Listings category, or a Listings sub-category. You can order the slideshow several ways by choosing a method in the “Auto Slideshow Order” setting. And you can control the maximum number of items to show in the slideshow by entering a value in the “Slideshow quantity” setting.
If you want more fine-grained control over what is showing up in the slideshow, and in what order, you can use the “User Defined Slideshow Order” setting. In it, type in the post ID numbers that you want to show up in the Slideshow, separated by a comma and space. For example: 45, 32, 67, 10, 89, 3. If you use this setting, then the “Slideshow Quantity”, “Category for Slideshow”, and “Auto Slideshow Order” settings will do nothing. It overrides all those settings.