Steps:

1.Select the resource Gantt chart.
2.If the resource Gantt chart is not currently displayed, display by selecting [Window] – [New Resource Gantt Chart] in the menu.
3.Hold down the Shift key and select the target cells to which the bars you want to drill down are assigned.The selected cells will be highlighted.
4.Right-click on one of the selected cells to display a popup menu. Select [Drilldown] from the popup menu.Tasks of the operations in the selected cells will be displayed individually in separate rows.

To close the drilldown display, click [-] on the left of the resource name.When you display the popup menu, you need to right-click on a portion of the cell to which the bar is not assigned.