1. Click the gear icon at the top right corner, then click Options.

2. In the navigation pane, under Calendar > Shared calendars, select Calendar Publishing.

3. In the calendar drop down menu, ensure that your desired calendar is selected.

4. Select desired permission level from the drop down menu, then click Save.

5. Two links will appear at the bottom, an HTML link and an ICS link, respectively.

6. Right click the ICS link and select copy link address.