To schedule a recurring shift, select how often the shift should recur under Repeat function when creating a new shift.
You'll be able to specify the frequency, days of the week and duration for the recurrence.
Then, just fill in the shift details as you normally would. Once saved, the shift will repeat on the schedule. This can be applied to unassigned and assigned shifts. Available shifts do not offer the recurrence feature at the moment.
Please note, you cannot edit a single shift to make it recurring. You can only create recurring shifts from the New shift window.