Make sure that you have installed to the correct target folder and that you have used the Readme to find the content.
How to Install Content into DAZ Studio 4
https://helpdaz.zendesk.com/entries/20659227-content-configuration-in-daz-studio-4
Finding Content in DAZ Studio in the Content Library Tab
https://helpdaz.zendesk.com/entries/21270966-finding-content-in-daz-studio-in-the-content-library-tab
ADDITIONAL RESOURCES
Import Mapped Directories
https://helpdaz.zendesk.com/entries/20643848-how-to-bring-existing-content-into-daz-studio-4
How to Map a Directory in content library in DAZ Studio 4
https://helpdaz.zendesk.com/entries/20978856-how-to-map-a-directory-in-content-library-in-daz-studio-4