Here is a utility that might help;
http://www.sharecg.com/v/71453/browse/10/Software-and-Tools/Daz-Content-installer-from-Zips
The runtime folder is where you install content intended for Poser (which DAZ Studio can use except for dynamic clothes which need to be made for DAZ Studio). It's been a while since I last used DAZ Studios but I would imagine that props go into props folder. Just a guess. I do remember that any time I wanted to load anything that was not include I would just use the import function.
Sorry if I was not more helpful.