Quick Summary

You can create one or more Roles, for example Doctor, Forensic Scientist, Teacher
You can assign each of these roles to one or more contacts
Each contact can have multiple Roles
When a contact is given a role, a start date must be specified
Adding an end date is optional

Watch the walkthrough

You have to be an Organisation Admin to create and edit Contact Roles however any user can assign one of those Roles to a Contact

Manage Roles

Roles box on a Contact Profile Page