During the install process of DAZ Studio, you can see two install targets:
One is DAZ Studio 4 x.xx, which is the folder, that contains the app exe.
the other one is 
Studio (at least in my case) which is the folder, that contains your assets. You can set the path, where ever you want on your computer, EXCEPT your DAZ Studio 4.x. folder.
Do NOT install your assets there ! Keep App folder and assets folder separate from each other!
Your assets can go again either into "My Library", "Content" or "My DAZ 3D Library"
I highly recommend 7zip as a unzipping app.
Open your zip file and select and unzipp everything under "content" or "My Library" or that contains "data" "product/Vendor name" and "Runtime" into your asset path.
Done!