From the Report Viewer, you will be able to see the name of the report along with a short description. You can sort and filter data but clicking on any header. You can also Export to CSV, Customize or Delete the report.
A short description of headers is available when you mouse-over a specific field.
Every report has a curated graph associated with it, but you can customize graphs by clicking on Customize. From there you can edit the graphs to fit your need. If you filter data out of your report, these changes will be reflected directly in your graph.
Note: Graph customizations are stored in your browser cache. Keep in mind that if you need to empty your cache, your changes to the graph will be reverted.