When you install JFBConnect, it will detect what 3rd party extensions you use and install the proper plugins. So, for instance, if you don't have Community Builder, we won't install the CB plugin.
If you have Virtuemart installed, the VM plugin should have been installed. To use, please:
* Go to the Joomla Plugin Manager
* Enable the Social Profiles - Virtuemart plugin
* Configure the profile import options in the JFBConnect -> Profiles area
I hope that helps, but if you have any other questions, just let me know.
Thanks,
Alex