Steps to Select All Shifts:
Go to the Calendar view of your schedule — this can be done at either the team or organization level.
Use your cursor to drag and drop over the desired date range (this can be specific days, a full week, or even an entire month).
After highlighting the range, a panel will appear on the right-hand side.
Click on “Select All Shifts” in that panel.
Here is a close up of what you should see on the left when you click on "Select All Shifts".