Download the program from Daz.  Double left click on the .exe file.  I think it asks you  to either pick Daz Studio or Poser 5, pick Poser 5. It will search for your Poser runtime folder.  Once it finds it, accept all the rest of the actions.

After the file is installed, open up Poser.  Once Poser is open, look in the library on the right side under "Figures" and then "Daz People".  V3 will be in there.

If you bought the head and body morphs and installed those, they will be found in the Pose part of the library, inside Poser.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi