1. Create an application

As call back use https://<Jtel Portal Host>/CarrierPortal/pages/acd/inbox/AcdInboxes.edit.xhtml

2. Create secret

Save the secret value somewhere it will not be accessible later. 

3. Add permissions.

4. Get clientID and tenantID

5. Configure mail box in portal

You will find further information in "Inboxes and edit e-mails"

6. Accept access to the mail box