If you're already using traditional Milestones and would like to convert an existing Milestone to a Sprint, Codebase can do that for you.
To start navigate to your main Sprints overview page within your project, either via the All Sprints link within the Tickets dropdown:
Or via the Sprints heading in your project overview:
Next click the Convert from a milestone button to the right of the Sprint Management page:
Select the existing milestone in the Milestone dropdown, then enter a name, goal and from / to date for the sprint. Finally click Create Sprint from Milestone to finish.
Now any linked tickets to your milestone will be presented in the form of a Sprint.