Items listed in the Data panel on the left of the report can be dragged and dropped onto the report to create new columns. Note that this requires careful placement of the cells. Drop the cell on the edge of the column it will appear next to. A narrow box will appear to indicate it’s time to drop. A column should then appear in the table. If you make a mistake, click the undo arrow in the tools.
A column can be removed in the following ways:
Find the item listen in the data source and right-click. Select "Delete > "Column".
Right click on the column itself and select "Delete" > "Column".