To add a table to the query, simply drag it or double-click from the left panel to the Graphical View area. To include a table field in the query, check the left of the field name in the list. To include all the fields, click at the left of the table caption.

To remove the object from the Graphical View area, click the cross button at the object caption.

Hint: You are also allowed to set criteria by right-clicking any fields from the Graphical View area.