Answer
Two prerequisites: the Apps10 environment needs to have at least UPD8 deployed, since the CRM Panel isn't available on earlier update levels; and the add-in itself needs to be installed into Outlook via a setup script, typically provided by your IFS CRM implementation consultant/partner, rather than through a standard permission-set-only grant — granting application-side access alone isn't sufficient without also running that add-in installation script on the user's machine.