To allow Milestones to be configured for the event:
  1. Navigate to Fundraising > TeamRaiser
  2. Enter the name of the event in the search field
  3. Click Search
  4. Under the Action column, click Edit
  5. On the left hand navigation pane, select Select Event Options
  6. Under Related Actions, select Edit Advanced Options
  7. Select Define Fundraising Options
  8. Scroll down to Fundraising Milestones
  9. Mark the checkbox 'Yes, milestones can be created for this TeamRaiser event'
  10. Click Save

If you are unable to see these all of the steps above, please contact support and reference this article.