How do I create shifts when creating an opportunity?

How do I create shifts when creating an opportunity?

In Add Opportunity, on step 4/6 > Click Create Shifts
1. Add a single date or indicate a date range
  1. If date range is selected: select the start date and end date, then select the days of the week as to when the shifts will occur 
2. Select the start and end time of the shifts
  1. If there are multiple time slots happening on the same day, click "+" to create additional time slots
3. Add the # of spots available for volunteers to book

4. Indicate if the time slot for the shift is flexible
Flexible means that volunteers can book an arrival and departure time between the stated start and end time of the shift(s), as long as it meets the minimum duration. 
6. Click Generate Shifts

7. Review all the shifts that were added for the opportunity on the right-hand side (See image below)

8. Click Confirm