In Ringotel Shell, you can add users to your PBX connection either by creating each one manually or importing all at once from a CSV file.
If you decided to stick with the last option, please keep in mind that a CSV file must be in a specific format:
The first line of the file should contain column headings.
The following headings are allowed:
name - (required) display name of a user
extension - (required) PBX extension of a user
password - (required) SIP password(secret) of a user
username - SIP username of a user
authname - authorization name of a user
email - user email. If specified, provisioning instructions will be sent to this address.