Okay... so you are referring to content not purchased from Daz3D which includes the installer, right? In that case, it's really very easy.

If you open up your Poser runtime folder, you will see directories for all of your digital assets. 

Runtime-
-Geometries
-Libraries
---Camera
---Character
---Face
---Hair
---Hand
---Light
---Materials
---Pose
---Props
-Textures

This list was over-simplified, but the directories listed above are the basic file folders you will need to be concerned with for most products.

Within Daz Studio, you will also find a Runtime folder within your Content directory. This Runtime folder is set up exactly the same as Poser's. In order to make manual installation uniform for everyone, content creators have to create a Runtime folder and place their created assets within that folder inside the appropriate sub-directory before creating their zip files. That way, after you unzip the file, all you need to do is copy the folders from the merchant's Runtime folder into the appropriate Runtime directory within Daz Studio. 

Does this make sense to you?

Regards,

Dave Frohmader (Nagus)

DAZ Studio for Beginners Tutorials