Hello @largefile0102,
ProfileGrid works with the WordPress users. If users are registered on WordPress site, then you may assign the group to users from “ProfileGrid >> Members” and users can use the plugin features.
You may also assign the group to users by editing their profile and configure the option “User Group(s)” in dashboard.
Plugin also allows to import the users in group on site using the CSV file. You may import the users from “ProfileGrid >> Global Settings >> Tools >> Import Users” in dashboard. For more details on this, please visit the link: https://profilegrid.co/tools
I hope this helps, let us know if you have any other questions.