Users can be added manually or imported. 

Use this spreadsheet to generate a user import .csv file: (usually used for new site trainings)
 https://docs.google.com/spreadsheets/d/1xoP6LY6g8wRJZHgEGrNaa_CwJ4WGmQP0ybQ2PtvoL5E/edit#gid=0 
The same spreadsheet can be used to generate a user import .csv file for email addresses.

Users are created in one of two groups, initially:

Basic Editor (or Manager) + a User Group specific to a category(ies) of articles 
or  
Admin 

Registered might the default user group, but registered does not give a user access to the backend of the website. 

Users should also be added to Email Lists Spreadsheet so Lori can input them into MailChimp. 

If a user gets access to an entire category, that user group can be allowed all 6 settings: 

If a user gets access to only one or more articles in that category:
Then deny or allow access to each article in that category respectively.

 Then they should see other articles grayed out 

How to create and set permissions for a user group

How to set up a registered section of the website