The Custom Report Builder is a visual design tool for analytics. With it, you can take any report in the UI and customize it to suit your needs. You can also create new reports using any variety of visuals in the form of widgets including data widgets, meters, donut charts, bar graphs, line graphs, and tables.
Every object is fully customizable for different dimensions (e.g. campaign groups and channels) and specific data metrics (e.g. impressions and visits).
When you're done with editing the type of widgets and their specific dimensions and data metrics, you can create any type of visual layout you want by simply moving or re-sizing the widgets to give your report the most ideal look.