If the zip file is set up with the paths already in it, just unzip it to XYZ:Program FilesCurious LabsPoser 5; if not, the internal file structure for Poser 5 is identical to Poser 4. You are correct, the PNG in Poser 5 serves the same purpose as the old .rsr file; however, Poser 5 will read .rsr files from Poser 4. Note that you don't need both a PNG and an .rsr for a library file. Just delete the larger of the two. Right now, the Install feature of Poser 5 isn't fully supported. Curious Labs hopes to correct this very soon.