A Prism project can contain many data tables.

Click the new button from the Sheet section of the Prism toolbar (or drop the Insert menu) and choose New Data Table and Graph.

The New Data Table and Graph dialog looks a lot like the Welcome dialog (with fewer choices). Choose which of six kinds of data tables you want, and whether to start with an empty table or use sample data. If you choose to create an XY or Grouped table and are not using sample data, you'll also need to decide about subcolumn format.