1. Click your avatar in the top left corner.
2. Click Personal Settings.
A new window will open bringing you to the Calendars page of your Outlook account.
5. Click Shared Calendars.
6. On the right side of the pop-up, under Publish a calendar, choose the calendar you want to share, the permissions you want to give, and click Publish.
7. A drop-down will appear below with an HTML and ICS link. Click on the HTML link and click Copy link.
8. Return to Thread and under Shared Calendar URL in Personal Settings, paste the link.
9. Click Save.
10. You can view shared calendars on the Calendars page on Thread.