If your Schedule Mode is "Critical Chain", do not forget to select the Planning Mode. The Switch to Tracking Mode () button must be displayed in the Main toolbar.
Log in to the HTML5 client.
Select the Work workspace, Gantt tab.
Select a project in the Project Data Selector.
Select the Scheduler () mode.
Click on () and () arrows displayed in the leftmost task’s name in the Gantt spreadsheet. It is then possible to collapse or elapse levels one by one.
OR, click on the Summarize () button available in the Gantt toolbar to display the Summarized At Level popup where you can specify the level of detail (number of levels of descendant tasks) to display.