Each Item within a project has a workflow status applied to it. This workflow status allows you to keep track of where that Item is in the production and reviewing process. Each workflow status can have a due date applied to it to help keep the project on track.
Your workflow is unique to each project, and is fully customisable from the Workflow tab, and you can edit this to match the steps your content goes through to get published.
You can see an overview of where a project is at from the Account Dashboard, or from the Overview tab within a project. This shows you what percentage of Items are in each status within the project.
You can also see in the project Overview tab a list of all the Items that you're assigned to, and a feed of recent project activity.