The C1Olap Web Part has three sections, the Toolbar, the Data Panel, and the Windows. The Toolbar and Data Panel are used to choose and configure the data displayed in the Grid and Chart Windows (highlighted).
When you right-click on a field anywhere in the Data Panel, you can customize its display in the Grid and Chart windows (see Customizing Fields), as well as move the field to the Filter, Column Fields, Row Fields and Values areas. A field can only be used in one of those areas at a time.
Double-clicking on a cell within the Grid window will expose drill-down data about that cell. See Drilling-Down on Your Grid Data.