Open Google Calendar
On the left, find “My calendars”
Hover over the calendar you want to share
Click the three dots (More) next to the calendar
Select “Settings and sharing”
Under “Share with specific people,” click “Add people”
Enter the email address or Google Group email
Choose a permission level (See only free/busy, See all event details, Make changes, or Make changes and manage sharing)
Click “Send” (or “Add”)
To share with a wider audience, under “Access permissions,” enable “Make available to” (if shown)
Select the access level you want (e.g., “See all event details”)
Click “Save”
To share a calendar link, use “Get shareable link” (if shown) and copy the link
To stop sharing, in the “Share with specific people” list, click the permission dropdown and select “Remove” or delete the person/group