Answer:
If you are a user with the appropriate authority (Admin, Parent Calendar Admin, Editor) then you can give permission(s) to users on a per calendar basis by doing the following:
- Click your name/picture in the top right corner
- Click Account Admin from the dropdown menu
- Head to the Team Members section found in the top left
- Hover over their name and a View/Edit Member link will become visible.
- Click the View/Edit Member link
- Select the appropriate role for each calendar
- Click the blue Assign Roles button at the bottom of the overlay