First of all, close your audio software application (DAW/Host).
Open Flux:: Center and go to the preferences page by clicking on the small cogwheel button up in the right corner, and enable the plugin fomats that are supported by your daw/host. The available Install Options may look different depending your operation system.
Click 'OK' to go back to the Center main installation page, and install the Studio Session Plugins and Studio Session Analyzer installers.
To activate the license for Studio Session Pack, open the iLok License Manager software, log in, and activate the Studio Session license.