The individual WindowsWorkflow steps are called Activities. Some activities are only designed for interactive WindowsWorkflows.
Activities are predefined building blocks that are strung together executing either unattended (sequential) or with user interactive (navigational).
For a complete list of the Tera specific activities, see:
http://tech.teradp.com/tech/html/gn4/docs/VSdoc/frlrfTeraDPGN4WorkflowActivity.html