There are a couple of differences between Users and Roles. It is important to understand the difference because these two are the primary areas to configure access to the Admin Portal, the Video Portal, and making changes to account settings.
In Users
Create Login Credentials for the Video Portal -> View the Camera Portal and Events
Create Login Credentials for the Admin Portal -> Admin permission to modify account settings, modify camera settings, and create other users
Choose what Roles for each User
Change User Credentials and view the history of a User's actions
In Roles
Choose which Portal this Role is able to log into (Admin + Video or just Video)
Choose which Cameras this Role can access (different locations, temporary access)
Choose which Users for each Role
Choose which Basic Abilities for each camera is accessible by this specific role (View, Share, PTZ, Update/Delete, Save Clip)