To open the Sample Contents window:
From the Control Center, expand the object tree until you find the Catalog Tables folder, the Views folder, or the Databases object. From the Databases object, select a database with which to work and expand that database to see the Tables folder.
Click on the table related folder. Any existing tables are displayed in the pane on the right side of the window (the contents pane).
Select the table you want in the contents pane and select Sample contents from the pop-up menu. The Sample Contents window opens.