Who within your Organisation is going to be using Workbooks?  Make a list of who they are and give some thought to which areas of Workbooks you want them to be able to use.

When creating a new User you can specify:

• Which Edition and Extension(s) they can use.
• Which Own Organisation(s) they represent.
• Which User Groups they belong to (and thus what Capabilities they have).
• Which authentication method they are able to log in through, whether it be Google, Microsoft etc.

After creating a new User you can:

• Assign records by using the "Assigned To" field within the different record Form Layouts.
• Run automatic processes and assign API Keys to specific users.
• Grant access to certain Databases. 
• Change password within User record.