If you use winrar just open the archive and drag the file onto the studio content folder.
Next Windows will ask you if you would like to merge runtime folders click yes.
Viola you are done.

PS. this only works if the files are setup for poser use.

If the files are for Daz Studio use you may have to drag the file onto the Studio folder.

You can see if it is for poser if the file is set up as runtime or Runtime if it has Content for root then it has been setup for Daz Studio.

Hope this helps.