Click on "Milestone" element (1) and Drag it on to the canvas:

A new Milestone is added to the right:

In case you need to delete Milestone, click "X" button (2) or context menu item of the Milestone header (3):

Open context menu item of the Milestone header and select where to move Milestone (4). Whatever elements were in that Milestone will stay with.

Steps can be moved from one Milestone to another by simple dragging with mouse. To move more than one step at a time select them (outline with mouse) first:

Mouseover the line (5) to highlight it. Drag the line (dashed line (6) shows new Milestone width).

Click on the Milestone header (7) to show it's properties:

• Name (8) - edit it if necessary
• Description (9) - populate for your assistance (optionally)