I am rebuilding a commercial real estate's website (very early). Eventually I will need to have a property listing page. They use a system called Astro Applications, which organizes their listings, and has tools to help clients display their properties. The problem I am having is getting what I need. Astro said they haven't heard of Squarespace, and only did templates for Wordpress before. He handed off to me a few .php files (he called it documentation), and said he could send over the XML calls the current website is using. I had no idea what to do with them. He also mentioned something about the API key, but I wasn't sure if that was right. Does anyone know what I need to bring these listings from their current site to the new one? Here are the php files he sent to me.