- select a group header;
- set its "OutlineExpression" property to any valid expression (e.g. group condition value);
- you may set the data band's OutlineExpresssion property as well.
This will create the hierarhic outline (also known as document map, table of contents) and display it in the preview window. When you click on the outline items, FastReport navigates to the item's page and its on-page location.