A workflow is a series of activities/steps that are necessary to complete a task. Each step in a workflow has a specific step before it and a specific step after it, with the exception of the first and last steps. In a linear workflow, the first step is usually initiated by an outside event. If the workflow has a loop structure, however, the first step is initiated by the completion of the last step.
Example workflow: A shared conference room needs to be managed on a first-come-first-served basis. Assigned users would be able to reserve the conference room if it is available. Otherwise, the invitation will be declined automatically by the resource calendar.