The user manual is accessible direct from the plug-in or application user interface.
In Pure Analyzer and Studio Session Analyzer, press the question mark ? in the top menu on the user interface and a window will open with a button giving you direct access to the user manual.
In all plug-ins, click on the small cogwheel button and a settings window will open which also contains a link to the user manual.
On the Flux:: series plug-ins, the cogwheel button is found in the upper right corner of the plug-in GUI.
On the Ircam series plug-ins, the cogwheel button is found in between the meters in the main output section to the right of the plug-in gui.