Project Page
Location of project milestone page
The page with the project milestones can be found in each project on the left sidebar. When it is opened for the first time, no milestones exist.
Create milestone
You can simply add milestones by clicking on the create milestone button in the top right corner. The following dialog appears and you can insert the milestone details
Title
Description
Start date
Completion date

Create milestone dialog
After creating a milestone, it appears in the list.
Project header
On top of the page you find a header with project name, project start and completion dates. Those dates can be changed by clicking on the edit icon next to the dates. The edit icon is only visible for project or Jira system administrators. When clicking on the edit button a dialog appears where the dates can be updated.

Edit project dates dialog
You can either set the dates manually, or set it automatically based on the milestone dates. If the checkbox is checked, the date selection fields on top are disabled. In that case the start date will be set to the earliest start date of the existing milestones, whereas the end date will be set to the latest milestone completion date.
If the checkbox is checked, the dates update automatically when a new milestone is created earlier or later than the existing ones or when existing milestone dates are changed accordingly.
Milestone list
The list is sorted by completion date. For each milestone a checkbox exists with which the milestone can be marked as completed. If you do so, the background changes to green. If you hover over the title, the description is displayed as additional information. Furthermore, you see the planned start and completion date, and a status.

Milestone status
The status can have one of the following values:
NEW Milestone created and no issue mapped to it
IN PROGRESS Issues are mapped to the milestone and not all of them are resolved
READY Mapped issues are all resolved, meaning the milestone is ready to be completed
COMPLETED Milestone has been marked as completed
By clicking on the edit icon, you can modify the details of each milestone.
Milestone issues
If issues are mapped, an expand icon is displayed on the right. Click it to expand the list of issues with information like key, summary, status or resolution.

Milestone with issue list expanded
Map issues to milestone
To map other issues to the milestone click on the map issues button to open the respective dialog.

Map issues dialog
You have 2 options here. Either pick issues in the select list on top to map them to the milestone. Or do that automatically by checking the checkbox below. When opening the dialog, you get immediately displayed which issues from the current project have a due date between start and completion date of the milestone you want to assign issues to. In the example above, those would be 5. If you decide to add them automatically, you don’t have to select them all in the select list. When the checkbox is checked, the select list above is automatically disabled and no more issues can be picked there.
Map issues to all milestones
Issues can also mapped to all milestones at once based on due date. To do so, open the respective dialog by clicking on the button Auto Map Issues on top next to the create milestone button.

Project header with Auto Map Issues button
The dialog shows all existing milestones and the number of issues that fit to them according to their due date. By clicking on the numbers, a new tab opens with the underlying JQL search.

Automated issue mapping dialog
For each milestone a checkbox can be selected or unselected. For unselected milestones the issues won’t be mapped. For all checked milestones the mapping is done automatically after you click on submit.
You can also display and edit the mapping directly in an issue. See this page for details: Issue Panel