Progress milestones are supported by:
A milestone represents a level of progress on an activity. Progress may be independent of effort due to rework and other factors
Milestone control from Product Detail Pane shown, others similar
The milestone editor displays as all or part of a tab in the detail pane of the above four project elements. Instructions to open a detail pane...
To edit an element's milestones, select the Edit button at the bottom of the detail pane. All milestones share these properties:
When complete select the Done button at the bottom of the detail pane