Dimensions are how you report measures. In other words, you select how to group or filter the measures. You must have at least one dimension selected in the Dimension Group section for the report to run. The most common configuration is one dimension for the x-axis, but you can add one dimension for the y-axis or a dimension for both axes. In the Dimension Filter section, one or more dimensions can be selected as a way to include or exclude a subset of the data that is returned. You can select an unlimited number of dimensions to filter by. When you select a dimension to either group or filter by, additional options are displayed for you to further refine the report results, if needed.