Under "Settings" at the top of the Path, select "Change access."
Under “Availability,” you'll see the option to "Limit learner access." Toggle this button on.
Select the calendar icons to pick start and/or end dates for your group. Learners will only be able to access the course between these dates. Save your changes and exit.
If you have multiple cohorts, you will need to adjust the access settings on each cohort.