The Milestone report page (Project menu > Plan > Milestone report) will show you the milestones for all your stages of the project. It is intended that this is used by project managers to give an overview of how the milestones on the project are tracking.
Expand the stage to see the underlying milestones. If the page is empty, have a read of How to add a milestone.
The planned date column shows when the milestone's scheduled completion date.
The actual column is the difference (in days) between the milestone completion date to today’s date.
The milestone report is not available to Synergy Professional and Synergy Business users.