Log in to the HTML5 client.
Select the Work workspace, Gantt tab.
Select a project in the Project Data Selector.
Select the task you want to track.
In the Task panel, select the Task Form tab ().
In the Tracking section, select a date in the Completed Date field.
Click on the Cmd () gear button of the task you want to track.
Select the Edit Task details command to open the Task Details dialog box.
In the Definition folder, Tracking section, select a date in the Completed Date field.