Open Google Calendar
Sign in to your Google account
In the left panel, find My calendars
Hover over the calendar you want to share
Click the three dots next to the calendar name
Select Settings and sharing
Scroll to Share with specific people or groups
Click Add people and groups
Enter the email address of the person you want to share with
Choose the permission level
Click Send
To make a new shared calendar, click the plus sign next to Other calendars
Select Create new calendar
Enter a calendar name
Click Create calendar
Open the new calendar’s Settings and sharing
Add people and groups
Set sharing permissions
Click Send