There are two permission levels for Flow, these are set in the Site Configuration in Fotoware Veloz. At least one of these permissions needs to be selected to enable Flow.
 

View Flow -  Allows users to view all workflows configured for their tenant. Users with this permission can access the Dashboard and see each workflow, but cannot create, edit, delete, enable, or disable workflows.

Manage Flow - Grants full access to all workflow functionality, including creating, editing, deleting, enabling, and disabling workflows.