You first have to install the DSON importer into Poser's main directory:

http://www.daz3d.com/dson-importer-for-poser

Then the DSON companion files go into an additional "Genesis" runtime you have to link to Poser.

Then you can load Genesis figures into Poser.

BUT...Some things like the scaling are completely broken and the bends are also inferior compared to using Genesis in Studio.