First and foremost, Genesis 3 is not DSON compatible, ready or whatever you want to call it. DSON is only for Genesis and Genesis 2 bases figures and the morph sets. Genesis and Genesis 2 use standard UV mapping and the DAZ proprietary Triax WM rigging in DS. It is converted to Poser's WM rigging (P9 and up) via the DSON importer. Genesis 3 uses a completely different rigging and UV mapping. It has dual quaternion rigging and UDIM mapping. Neither of which is supported by Poser.

If a product for Genesis and Genesis 2 have Poser Companion Files, they will be part of the download. You can create your own Poser Companion Files but you must have DS installed to create them. Without Poser companion files, the duf (or older DS files) that you import into Poser will not work. If you simply want to load props, Dimension 3D has a free DSON loader script on his site. You must have it and the DSON installed. The loader script will load most props into Poser. If it is a large prop, it may take a while and sometimes it fails. Also be aware that you will have to adjust the material settings. Poser and DS have different render engines so the material settings are much different.