Before You Begin: This functionality isn’t available for V1 reports.
If the report you’re working on is based on a report topic, the dataset is made up of the data entities that the topic contains. If you started the report with a new dataset, it only contains the primary entity until you add more fields. In both cases, you can add more entities and fields to the dataset using the functionality in the Add a Field screen, which you open by clicking Fields > Add Field in the report designer.
The following topics contain information about adding and removing fields and entities to a report's dataset: