A milestone is an action or event marking a significant change or stage in your project. The finish date for a milestone is the same as its start date. A milestones is represented by a grey diamond image in the Gantt chart, centered on the provided start time.
To create a milestone:
Click Gantt View on the toolbar to display your sheet in Gantt view or to add a Gantt chart to your sheet.
Enable dependencies on your sheet (click
Edit Project Setting in the far-left corner of the Gantt chart and check the Dependencies Enabled checkbox). - Enter a task duration of 0 (zero), and a start date, to create a milestone.
TIP: To create an extended milestone, enter a task duration of ~0, and a start date. An extended milestone requires one full working day to complete, but is still represented by a diamond shape in the Gantt chart.