How do I give a user permissions/access to individual calendars?

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