The Reporting Tab is where you build out your Information Model, i.e. the view that users will see when they log in to the Flow Server using their web browser.
Any Charts, Dashboards, or Dashboard Loops that are added to the Reporting Tab must first be contained within Folders. This ensures proper organization of your information model. Also, Folders are used to restrict access to authorized users.
For more information on what you can create in the Reporting tab, see the following articles: